A timeline by wilcoxchar with a point of divergence around the Nullification Crisis. Wilcoxchar started it in February of 2009, and the TL is currently up to 1912 and the end of the Great War. It can be found on the discussion board here. Union and Liberty is an extremely prominent timeline, as it is both old, long, and excellently written.
Andrew Jackson makes lowering tariffs one of his promises in the 1828 presidential election. In 1830 when the issue of tariffs comes up in South Carolina, Jackson is sympathetic to the South Carolinian views and instead of threatening military force, Jackson compromises and does not alienate Vice President John C. Calhoun. Jackson keeps Calhoun as his running mate in the 1832 election and in 1835 when Jackson is assassinated, Calhoun becomes the president of the United States.
Jackson's softer policies led to a somewhat fairer treatment of the native Americans in the southeastern United States. Some tribes were compensated for their land and moved west voluntarily while others were allowed to stay on a small portion of their land for a price. In 1835, Andrew Jackson was assassinated leading Calhoun to take the position of Acting President until he was elected in 1836. During Calhoun's presidency, the United States defeated Mexico in the Mexican-American War. The United States, rather than taking land, affirmed the independence of the republics of Texas, California, the Yucatan, and Rio Bravo.
In world affairs, Belgium gained its independence from the Netherlands. While the Dutch were able to keep all of Limburg, Luxembourg, and Liege, they ceded claims on Borneo to Belgium. The possession of Borneo would be a springboard for Belgium to launch further colonial adventures later in the 19th century.
During the presidency of William Henry Harrison, the United States was dominated by the Whig ideals as Henry Clay passed the national bank and the American system through the Senate. In 1844, Clay's ego got the best of him and he ran for the Whig nomination against Harrison. After losing the nomination, Clay refused to support Harrison's campaign and lost the White House for the Whigs. Democrat James K. Polk was elected and immediately annexed Texas into the United States. Polk also oversaw the Oregon War between the United States and the United Kingdom. The United States defeated Great Britain and gained Oregon Territory up to the 52nd parallel as well as some minor expansions near the Great Lakes and in Maine. Polk's presidency also saw the purchase of Cuba from Spain and the exodus of the Mormons to California and British North America. Polk declined to run for reelection in 1848 and Winfield Scott was elected. Scott would be the last Whig to be president of the United States.
The 1850s in the United States were dominated by the issue of the expansion of slavery. With much of Oregon Territory gained in the Oregon War and future prospects of expansion into California or Mexico unknown, it was obvious that eventually the free states would outnumber the slave states in their representation in Congress. While Cuba was admitted as a slave state, the deadlock in Congress brought the Missouri Compromise under review and opened up both Kearny and Dakhota Territory for potential slave states. The Senate remained at a deadlock through Scott's term into the presidency of Stephen Douglas. An advocate of popular sovereignty as a way to solve the slavery issue, Douglas passed a bill in 1854 opening up Kearny Territory to settlement by all Americans. This created an inevitable clash between freesoilers and slaveholders in the territory. The outbreak of violence in Kearny led to Douglas's ousting in the 1856 elections and swept Samuel Houston into office.
Samuel Houston attempted to moderate the country's sectionalism over slavery in an effort to bring the American people back together by resolving the violence that started during the Douglas administration. Houston passed the Kearny Statehood Act in 1857 which divided the territory into two states. The northern state, Kearny, was admitted as a free state while the southern half was admitted as the slave state of Calhoun. Houston's administration was mostly peaceful, but underlying tensions were still present among much of the American population. These tensions boiled over when Vice President Bayard became ill and died and Houston was assassinated in the winter of 1862.
The 1850s in much of the rest of the world was a time of instability and colonial expansion. Starting off the decade was the Mid-Century Revolutions, which overthrew the monarchies in France and Sardinia-Piedmont and began the process of Italian unification. Meanwhile, Mexico faced further internal conflicts until the country completely collapsed in 1857 into several small states. Taking advantage of this, former Vice President Jefferson Davis carved out the city-state of Veracruz. In India, a rebellion by several local princes led to the British rolling back previous reforms and more consolidation of Company control on the subcontinent. Britain also expanded her colonial territory as a result of the Anglo-Siamese War in 1854 in which the United Kingdom gained much of the Malay Peninsula from Siam.
After Houston's death, the United States went into a constitutional crisis. There were ambiguous provisions for what should happen if both the President and Vice President died, and as Calhoun had only accepted the title of Acting President less than a year before the presidential election, there was confusion over what the powers of the Acting President were. President Pro Tempore of the Senate David Atchison became Acting President after Houston's death and a Joint Emergency Presidential Selection Committee was created to decide the next President of the United States. The committee settled on David Atchison, Speaker of the House Andrew Johnson, and Secretary of State William Seward as the three candidates for the Presidency and began the ballots for voting on the candidates. The committee's proceedings were subject to much controversy and during the selection, South Carolina and several other states seceded to form the Confederate States of America. Andrew Johnson was selected as a moderate candidate and as a president who was committed to preserving the Union.
The Confederate States rebelled and elected Howell Cobb as their first president. The United States quickly moved to crush this upstart rebellion, but the Confederacy held out, even making gains as far as Cincinnati, Ohio and Cape Girardeau, Missouri. In 1864 at the height of the war, the leaders of both the United States and the Confederacy were ousted by their electorates. Judah P. Benjamin was elected to the Confederate Presidency in March, and John C. Fremont was elected to the Presidency of the United States in November. Benjamin tried to forge a peace treaty with Andrew Johnson in the months before Fremont took office, but Johnson's efforts at negotiation were blocked by a pro-war Congress. The Confederacy surrendered to the United States in 1866, and the National War was over.
After the National War, the Republicans continued to control the presidency and Congress through the terms of John C. Fremont, Robert E. Lee, and Ambrose Burnside. Constitutional amendments were passed to grant freed African-Americans citizenship within the United States and the right to vote, but prejudice against blacks continued in a few Southern states. Through the 1870s, the American West continued to be settled as railroads snaked across the Great Plains. The Transcontinental Railroad was completed in 1874, finally connecting the Pacific coast of the old Oregon Territory with the rest of the country by rail.
Andrew Jackson (Democrat, 1829-18351))
John C. Calhoun (Democrat, 1835-18412))
William Henry Harrison (Whig, 1841-1845)
James K. Polk (Democrat, 1845-1849)
Winfield Scott (Whig, 1849-1853)
Stephen Douglas (Democrat, 1853-1857)
Samuel Houston (Democrat, 1857-18623))
David R. Atchison (Democrat, 18624))
Andrew Johnson (None/Democrat5), 1862-1865)
John C. Fremont (Republican, 1865-1873)
Robert E. Lee (Republican, 1873-18776))
Ambrose Burnside (Republican, 1877-1881)
Winfield Scott Hancock (Democrat, 1881-1885)
George Edmunds (Republican, 1885-1889)
Grover Cleveland (Democrat, 1889-1897)
Levi P. Morton (Republican, 1897-18987))
William Jennings Bryan (Republican, 1898-1901)
William McKinley (Democrat, 1901-1905)
Theodore Roosevelt (1905-present)
Belgian Borneo and East Indies
A split Mormon Exodus, to both the Great Salt Lake and Manitoba
Mexico balkanized into a dozen countries
A Greater Bolivia that includes southern Peru
ITTL, Walt Whitman is a politician, who served as a senator from New York and Vice Presidential candidate for Andrew Johnson in 1864
A Workers' Republic of Vienna that arose after the collapse of Habsburg Austria in 1870