After Zachary Taylor appointed Justin Butterfield rather than Abraham Lincoln (who was concluding his term in Congress) to the post of Commissioner of the General Land Office,
"..the administration tried to appease Lincoln by offering him the secretaryship of the Oregon Territory, which he promptly declined, urging that it be given instead to his friend Simeon Francis. Soon thereafter, as Lincoln was attending court in Bloomington with John Todd Stuart, a special officer arrived with an offer to appoint him governor of Oregon at a salary of $3,000 a year. Truly tempted, Lincoln asked Stuart if he should accept. His former law partner said he 'thought it was a good thing; that he could go out there and in all likelihood come back from there as a Senator when the State was admitted.' Lincoln, according to Stuart, 'finally made up his mind that he would accept the place if Mary would consent to go.' But she had no wish to live in a remote frontier and would not consent. Joshua Speed later told Stuart 'that Lincoln wrote to him that if he [Speed] would go along, he would give him any appointment out there which he might be able to control. Lincoln evidently thought that if Speed and Speed's wife were to go along, it would be an inducement for Mary to change her mind...but Speed thought he could not go, and so the matter didn't come to anything.' During her husband's presidency, Mary Lincoln liked to remind him that she had kept him from 'throwing himself away' by accepting the governorship of Oregon."
Michael Burlingame, *Abraham Lincoln: A Life, Volume One* (Baltimore: Johns Hopkins University Press 2008), p. 307. https://books.google.com/books?id=ldfcBd_-O8QC&pg=PT405
Suppose that Lincoln had succeeded in persuading Mary to go with him to Oregon--perhaps by inducing the Speeds to go there, perhaps by persuading her that being territorial governor of Oregon would offer a chance, as Stuart said, to get elected to the US Senate once it became a state. (This would both play to Mary's ambitions for her husband's political career and to some extent answer her concerns about living in a wilderness--you may be living in a wilderness at first, but it's a step to better things in Washington DC...)
This of course assumes that Mary's veto was the real reason for Lincoln's turning down the offer. Perhaps it was just an excuse and he didn't really want to go anyway, preferring to retain his legal career in Illinois as a basis for possible future political bids. But let's just assume that he really was as sorely tempted as Stuart maintained, and that he does get Mary to agree. So Abe and Mary set out for Oregon. What happens when the Democrats get back into power after the 1852 election, and Lincoln's term as territorial governor ends? (If the experience of John P. Gaines is an indication, the Whig Lincoln is not going to be terribly popular in mostly Democratic Oregon Territory http://en.wikipedia.org/wiki/John_P._Gaines though of course some of Gaines' problems may have been due to his personal political ineptitude, and Lincoln might have been more successful.)
One possibility is that the whole interlude won't actually change history that much: Lincoln will return to Illinois, resume his law practice, and get back into politics in 1854 when the Kansas-Nebraska Act presents him with an opportunity. Yet one wonders whether he could have done this as successfully as in OTL without the five added years of Illinois legal practice he got in OTL when he got to know many people and to sharpen his mind in a way that would be unlikely if he had been consumed with administrative detail in Washington DC (at the General Land Office) or in Oregon.
But there is another possibility: he stays on in Oregon, practicing law there and taking part in territorial and--later--state politics. He would take an early role in organizing the territory's Republican Party. At first sight, this seems to be a complete dead end for him. In its early years, Oregon was decidedly a Democratic territory and state (this no doubt is largely because many of its early settlers were Missourians). However, the split between Douglas and Buchanan Democrats--the latter being represented in Oregon by Joseph Lane, who was to be Breckinridge's running mate in 1860--could give Lincoln a chance to fulfill John Todd Stuart's prophecy and become Senator from Oregon after all. The key was the June 1860 election for the state legislature, which was ultimately to result in a coalition of Douglas Democrats and Republicans electing one Douglas Democrat (James W. Nesmith--see http://en.wikipedia.org/wiki/James_W._Nesmith for his background) and one Republican (Lincoln's old friend Edward D. Baker, https://en.wikipedia.org/wiki/Edward_Dickinson_Baker who had recently arrived in Oregon from California) to the US Senate:
"The Legislature chosen in this June election was again overwhelmingly democratic, but upon analysis it appeared that the two factions of the democrats in the joint assembly were divided nearly evenly, there being eighteen supporters of Douglas and seventeen adherents of Breckenridge, or Lane. The republicans, numbering thirteen, thus had the balance of power in the event the warring democratic factions should be unable to unite, which was precisely what did come to pass. Indeed, the result presaged the fusion of republicans and loyal or Union democrats which was to follow. While there was no formal alliance between republicans and Douglas democrats, there was at least general agreement as to method.13 The logic of this informal political compact was unassailable, for notwithstanding existing differences of opinion between the abolitionists and the champions of squatter sovereignty, both groups constituting a majority of the whole people of the state realized the perils of secession. Baker indeed refrained from committing himself to the extreme abolition view, making it easy for Douglas democrats to support him, and throughout the campaign he pursued a policy of persuasion rather than of invective.
"When the Legislature met September 10, 1860, at Salem, the prospect that the republicans and Douglas democrats would carry out their pre-election understanding was so imminent that six of the senators representing the Breckenridge faction absented themselves in a futile attempt to prevent organization of the senate,14 leaving that body without a quorum. They went into concealment, while the sergeant-at-arms sought for them in vain. Two rival conventions of the factions of the democrat party were then in session in Eugene, and these adopted resolutions respectively denouncing and upholding the conduct of the absconders. Governor Whiteaker, although allied with the Breckenridge faction, published an appeal to them to return for patriotic reasons, and they did so, September 24, 1860. The Douglas democrats meanwhile organized the assembly, electing Benjamin F. Harding of Marion, speaker. Luther Elkins of Linn was made president of the senate on its organization without a quorum. The joint assembly while waiting for the absentee members to return made several unsuccessful efforts to elect a senator, the Douglas men voting for Nesmith and Williams and the republicans for Baker and Holbrook. Being unable to proceed without the absconders, however, the two houses adjourned sine die. Governor Whiteaker then called an extra session, at which both houses had a quorum, and balloting was resumed ineffectually, October first.15 Ten ballots were taken, and there was an adjournment to October 2, at which time Nesmith and Baker were duly elected on the fourth ballot of the day, carrying the fusion of republicans and Douglas democrats into effect. Twenty-six votes were necessary for a choice; Nesmith received twenty-seven votes for the long term and Baker twenty-six votes for the short term. The pro-slavery democrats, the opponents of Nesmith, concentrated on Judge Deady, who received twenty-two votes. In opposition to Baker, Judge George H. Williams received twenty votes and Ex-Governor Curry two. The result had not been attained, however, without a bitter struggle in which the Douglas democrats made several efforts to find a basis of reunion with the Breckenridge faction which should include Nesmith and exclude Smith. So closely did the factions approach agreement that on the ballot preceding the final one Nesmith had twenty-four votes and Currv twenty- five, within two and one, respectively, of enough to elect.1* The fifteen democrats who voted for Baker joined in issuing a statement in justification of their act. They declared the 'prescriptive and intolerant course pursued by General Lane and his office-holding minions toward non-intervention democrats * * * and the corruption and treachery of Delazon Smith' [a pro-Lane Democrat, known to his enemies as "Delusion Smith", who had briefly served as US Senator in 1859--DT] to have been the direct causes of the party division, and contended that the election of a majority of non-intervention democrats to the Legislature had finally disposed of Lane and Smith. The Breckenridge forces, and Lane by implication, were branded as party-wreckers, and those who persisted in voting for Smith were charged with seeking to create a deadlock with a view to preserving a vacancy to be filled in 1862 by 'a rejected aspirant for vice-presidential honors.' [Obviously a reference to Lane--DT] In specific defense of their votes for Baker, the fifteen explained that they were influenced 'by his well known position upon the question of slavery in the territories--a position differing but little from that of our party.'..."
Charles H. Carey, *History of Oregon* (1922), pp. 643-645 http://books.google.com/books?id=ZUMOAAAAIAAJ&pg=PA643
If Lincoln had become an important Republican leader in Oregon, is it not conceivable that he rather than his old friend Baker might have been chosen as Republican Senator by the Republican-Douglasite coalition? (At least he would not be subject to the criticism that was made of Baker of being a recent arrival.) It is true that the above source emphasizes Baker's moderation on the slavery issue and his ability to conciliate the Douglas forces as essential to his election. (Indeed, Baker had gained fame in California and throughout the nation by delivering the eulogy on the Douglasite Senator Broderick, whose death in a duel with David S. Terry did so much to destroy the influence of the pro-Southern "Chivalry" in California politics.) One might think that Lincoln, whose "House Divided" speech gave him a reputation (not entirely deserved) for radicalism on the slavery question, and who firmly opposed the pleas of Horace Greeley and other Eastern Republicans to support Douglas once the latter came out against the Lecompton Constitution--would have a harder time winning Douglasite support.
But of course that assumes that Lincoln would still be as anti-Douglasite in Oregon as he was in Illinois. In Illinois, Republicans overwhelmingly rejected Greeley's pleas to support Douglas in 1858. Republicans in that state had already reached approximate parity with the Democrats in 1856 (they did not quite carry the state for Fremont but they did elect the governor) and naturally did not want to suddenly concede to the party they were about to overtake. And Douglas virtually *was* the Democracy in Illinois; the Buchananites may have had some support in "Egypt" in the southern part of the state but elsewhere did not amount to much apart from those dependent on federal patronage. If Baker had remained in Illinois (he moved to California after failing to get a position in Taylor's cabinet) he too would almost certainly have opposed Douglas. By contrast, on the West Coast (California and Oregon) where Republicans were weak and where the pro-Lecompton and anti-Douglas wing of the Democratic party was powerful, some sort of alignment with the Douglasites made much more political sense for the Republicans--indeed it was essential if they were to elect a Senator in Oregon in 1860. Lincoln as a practical politician would see this. True, he would be just as convinced in Oregon as in Illinois that Lecompton was wrong not just because it had been fraudulently enacted but because slavery itself was wrong and should not be extended. But as an Oregonian he would be more likely to believe that a temporary coalition with those who opposed the Buchanan administration's pro-slavery policies *for whatever reason* was justified and indeed necessary. And so I doubt that Lincoln the Oregonian would have delivered the House Divided speech, with its allegation that Douglas was part of a conspiracy to nationalize slavery.
And if Lincoln does get elected as Senator from Oregon in 1860? Let's say that in this ATL Seward gets the Republican presidential nomination that year. And let's say that Seward falls short in November because he loses the closely contested states of California, Oregon, Illinois, Indiana, and the electoral votes that Lincoln got in New Jersey https://en.wikipedia.org/wiki/United_States_presidential_election,_1860 and the election goes to the House. (OK, Indiana wasn't *that* close. But it could have been if Jesse Bright hadn't been so stubbornly anti-Douglas. Anyway, it's even conceivable that Seward would have lost his home state of New York, where he had some enemies in his own party, notably Horace Greeley.) It is possible that Breckinridge will win in the House (if he gets support from enough southern Americans/Oppositionists/Constitutional Unionists/Whigs), or a deadlock could develop that would make the vice-president chosen by the Democratic-controlled Senate (i.e., Lane) Acting President. Fast forward to 1864. The Republicans say to themselves "We lost in 1860 because Seward could not carry the Pacific Coast or enough of the Old Northwest. Maybe Senator Lincoln, who spent much of his youth in Indiana, whose political career started in Illinois, and who is now an Oregonian, is the man to carry these states this year. Besides, he's anti-slavery without being as radical as Seward was reputed to be, and he won't offend either the Germans or the nativists..."
Of course, even if Seward wins, Lincoln could still be on a Republican national ticket someday... (Note that OTOH Baker, even if he had not been killed in the ACW, could never have become President, because he was born in England.)
"..the administration tried to appease Lincoln by offering him the secretaryship of the Oregon Territory, which he promptly declined, urging that it be given instead to his friend Simeon Francis. Soon thereafter, as Lincoln was attending court in Bloomington with John Todd Stuart, a special officer arrived with an offer to appoint him governor of Oregon at a salary of $3,000 a year. Truly tempted, Lincoln asked Stuart if he should accept. His former law partner said he 'thought it was a good thing; that he could go out there and in all likelihood come back from there as a Senator when the State was admitted.' Lincoln, according to Stuart, 'finally made up his mind that he would accept the place if Mary would consent to go.' But she had no wish to live in a remote frontier and would not consent. Joshua Speed later told Stuart 'that Lincoln wrote to him that if he [Speed] would go along, he would give him any appointment out there which he might be able to control. Lincoln evidently thought that if Speed and Speed's wife were to go along, it would be an inducement for Mary to change her mind...but Speed thought he could not go, and so the matter didn't come to anything.' During her husband's presidency, Mary Lincoln liked to remind him that she had kept him from 'throwing himself away' by accepting the governorship of Oregon."
Michael Burlingame, *Abraham Lincoln: A Life, Volume One* (Baltimore: Johns Hopkins University Press 2008), p. 307. https://books.google.com/books?id=ldfcBd_-O8QC&pg=PT405
Suppose that Lincoln had succeeded in persuading Mary to go with him to Oregon--perhaps by inducing the Speeds to go there, perhaps by persuading her that being territorial governor of Oregon would offer a chance, as Stuart said, to get elected to the US Senate once it became a state. (This would both play to Mary's ambitions for her husband's political career and to some extent answer her concerns about living in a wilderness--you may be living in a wilderness at first, but it's a step to better things in Washington DC...)
This of course assumes that Mary's veto was the real reason for Lincoln's turning down the offer. Perhaps it was just an excuse and he didn't really want to go anyway, preferring to retain his legal career in Illinois as a basis for possible future political bids. But let's just assume that he really was as sorely tempted as Stuart maintained, and that he does get Mary to agree. So Abe and Mary set out for Oregon. What happens when the Democrats get back into power after the 1852 election, and Lincoln's term as territorial governor ends? (If the experience of John P. Gaines is an indication, the Whig Lincoln is not going to be terribly popular in mostly Democratic Oregon Territory http://en.wikipedia.org/wiki/John_P._Gaines though of course some of Gaines' problems may have been due to his personal political ineptitude, and Lincoln might have been more successful.)
One possibility is that the whole interlude won't actually change history that much: Lincoln will return to Illinois, resume his law practice, and get back into politics in 1854 when the Kansas-Nebraska Act presents him with an opportunity. Yet one wonders whether he could have done this as successfully as in OTL without the five added years of Illinois legal practice he got in OTL when he got to know many people and to sharpen his mind in a way that would be unlikely if he had been consumed with administrative detail in Washington DC (at the General Land Office) or in Oregon.
But there is another possibility: he stays on in Oregon, practicing law there and taking part in territorial and--later--state politics. He would take an early role in organizing the territory's Republican Party. At first sight, this seems to be a complete dead end for him. In its early years, Oregon was decidedly a Democratic territory and state (this no doubt is largely because many of its early settlers were Missourians). However, the split between Douglas and Buchanan Democrats--the latter being represented in Oregon by Joseph Lane, who was to be Breckinridge's running mate in 1860--could give Lincoln a chance to fulfill John Todd Stuart's prophecy and become Senator from Oregon after all. The key was the June 1860 election for the state legislature, which was ultimately to result in a coalition of Douglas Democrats and Republicans electing one Douglas Democrat (James W. Nesmith--see http://en.wikipedia.org/wiki/James_W._Nesmith for his background) and one Republican (Lincoln's old friend Edward D. Baker, https://en.wikipedia.org/wiki/Edward_Dickinson_Baker who had recently arrived in Oregon from California) to the US Senate:
"The Legislature chosen in this June election was again overwhelmingly democratic, but upon analysis it appeared that the two factions of the democrats in the joint assembly were divided nearly evenly, there being eighteen supporters of Douglas and seventeen adherents of Breckenridge, or Lane. The republicans, numbering thirteen, thus had the balance of power in the event the warring democratic factions should be unable to unite, which was precisely what did come to pass. Indeed, the result presaged the fusion of republicans and loyal or Union democrats which was to follow. While there was no formal alliance between republicans and Douglas democrats, there was at least general agreement as to method.13 The logic of this informal political compact was unassailable, for notwithstanding existing differences of opinion between the abolitionists and the champions of squatter sovereignty, both groups constituting a majority of the whole people of the state realized the perils of secession. Baker indeed refrained from committing himself to the extreme abolition view, making it easy for Douglas democrats to support him, and throughout the campaign he pursued a policy of persuasion rather than of invective.
"When the Legislature met September 10, 1860, at Salem, the prospect that the republicans and Douglas democrats would carry out their pre-election understanding was so imminent that six of the senators representing the Breckenridge faction absented themselves in a futile attempt to prevent organization of the senate,14 leaving that body without a quorum. They went into concealment, while the sergeant-at-arms sought for them in vain. Two rival conventions of the factions of the democrat party were then in session in Eugene, and these adopted resolutions respectively denouncing and upholding the conduct of the absconders. Governor Whiteaker, although allied with the Breckenridge faction, published an appeal to them to return for patriotic reasons, and they did so, September 24, 1860. The Douglas democrats meanwhile organized the assembly, electing Benjamin F. Harding of Marion, speaker. Luther Elkins of Linn was made president of the senate on its organization without a quorum. The joint assembly while waiting for the absentee members to return made several unsuccessful efforts to elect a senator, the Douglas men voting for Nesmith and Williams and the republicans for Baker and Holbrook. Being unable to proceed without the absconders, however, the two houses adjourned sine die. Governor Whiteaker then called an extra session, at which both houses had a quorum, and balloting was resumed ineffectually, October first.15 Ten ballots were taken, and there was an adjournment to October 2, at which time Nesmith and Baker were duly elected on the fourth ballot of the day, carrying the fusion of republicans and Douglas democrats into effect. Twenty-six votes were necessary for a choice; Nesmith received twenty-seven votes for the long term and Baker twenty-six votes for the short term. The pro-slavery democrats, the opponents of Nesmith, concentrated on Judge Deady, who received twenty-two votes. In opposition to Baker, Judge George H. Williams received twenty votes and Ex-Governor Curry two. The result had not been attained, however, without a bitter struggle in which the Douglas democrats made several efforts to find a basis of reunion with the Breckenridge faction which should include Nesmith and exclude Smith. So closely did the factions approach agreement that on the ballot preceding the final one Nesmith had twenty-four votes and Currv twenty- five, within two and one, respectively, of enough to elect.1* The fifteen democrats who voted for Baker joined in issuing a statement in justification of their act. They declared the 'prescriptive and intolerant course pursued by General Lane and his office-holding minions toward non-intervention democrats * * * and the corruption and treachery of Delazon Smith' [a pro-Lane Democrat, known to his enemies as "Delusion Smith", who had briefly served as US Senator in 1859--DT] to have been the direct causes of the party division, and contended that the election of a majority of non-intervention democrats to the Legislature had finally disposed of Lane and Smith. The Breckenridge forces, and Lane by implication, were branded as party-wreckers, and those who persisted in voting for Smith were charged with seeking to create a deadlock with a view to preserving a vacancy to be filled in 1862 by 'a rejected aspirant for vice-presidential honors.' [Obviously a reference to Lane--DT] In specific defense of their votes for Baker, the fifteen explained that they were influenced 'by his well known position upon the question of slavery in the territories--a position differing but little from that of our party.'..."
Charles H. Carey, *History of Oregon* (1922), pp. 643-645 http://books.google.com/books?id=ZUMOAAAAIAAJ&pg=PA643
If Lincoln had become an important Republican leader in Oregon, is it not conceivable that he rather than his old friend Baker might have been chosen as Republican Senator by the Republican-Douglasite coalition? (At least he would not be subject to the criticism that was made of Baker of being a recent arrival.) It is true that the above source emphasizes Baker's moderation on the slavery issue and his ability to conciliate the Douglas forces as essential to his election. (Indeed, Baker had gained fame in California and throughout the nation by delivering the eulogy on the Douglasite Senator Broderick, whose death in a duel with David S. Terry did so much to destroy the influence of the pro-Southern "Chivalry" in California politics.) One might think that Lincoln, whose "House Divided" speech gave him a reputation (not entirely deserved) for radicalism on the slavery question, and who firmly opposed the pleas of Horace Greeley and other Eastern Republicans to support Douglas once the latter came out against the Lecompton Constitution--would have a harder time winning Douglasite support.
But of course that assumes that Lincoln would still be as anti-Douglasite in Oregon as he was in Illinois. In Illinois, Republicans overwhelmingly rejected Greeley's pleas to support Douglas in 1858. Republicans in that state had already reached approximate parity with the Democrats in 1856 (they did not quite carry the state for Fremont but they did elect the governor) and naturally did not want to suddenly concede to the party they were about to overtake. And Douglas virtually *was* the Democracy in Illinois; the Buchananites may have had some support in "Egypt" in the southern part of the state but elsewhere did not amount to much apart from those dependent on federal patronage. If Baker had remained in Illinois (he moved to California after failing to get a position in Taylor's cabinet) he too would almost certainly have opposed Douglas. By contrast, on the West Coast (California and Oregon) where Republicans were weak and where the pro-Lecompton and anti-Douglas wing of the Democratic party was powerful, some sort of alignment with the Douglasites made much more political sense for the Republicans--indeed it was essential if they were to elect a Senator in Oregon in 1860. Lincoln as a practical politician would see this. True, he would be just as convinced in Oregon as in Illinois that Lecompton was wrong not just because it had been fraudulently enacted but because slavery itself was wrong and should not be extended. But as an Oregonian he would be more likely to believe that a temporary coalition with those who opposed the Buchanan administration's pro-slavery policies *for whatever reason* was justified and indeed necessary. And so I doubt that Lincoln the Oregonian would have delivered the House Divided speech, with its allegation that Douglas was part of a conspiracy to nationalize slavery.
And if Lincoln does get elected as Senator from Oregon in 1860? Let's say that in this ATL Seward gets the Republican presidential nomination that year. And let's say that Seward falls short in November because he loses the closely contested states of California, Oregon, Illinois, Indiana, and the electoral votes that Lincoln got in New Jersey https://en.wikipedia.org/wiki/United_States_presidential_election,_1860 and the election goes to the House. (OK, Indiana wasn't *that* close. But it could have been if Jesse Bright hadn't been so stubbornly anti-Douglas. Anyway, it's even conceivable that Seward would have lost his home state of New York, where he had some enemies in his own party, notably Horace Greeley.) It is possible that Breckinridge will win in the House (if he gets support from enough southern Americans/Oppositionists/Constitutional Unionists/Whigs), or a deadlock could develop that would make the vice-president chosen by the Democratic-controlled Senate (i.e., Lane) Acting President. Fast forward to 1864. The Republicans say to themselves "We lost in 1860 because Seward could not carry the Pacific Coast or enough of the Old Northwest. Maybe Senator Lincoln, who spent much of his youth in Indiana, whose political career started in Illinois, and who is now an Oregonian, is the man to carry these states this year. Besides, he's anti-slavery without being as radical as Seward was reputed to be, and he won't offend either the Germans or the nativists..."
Of course, even if Seward wins, Lincoln could still be on a Republican national ticket someday... (Note that OTOH Baker, even if he had not been killed in the ACW, could never have become President, because he was born in England.)