Some thoughts prompted by a reading of Jack Ross, *The Socialist Party of America: A Complete History* (2015):
By 1916 Eugene Debs was tired of running for president (though he was to do so one more time, in 1920, largely as a protest against the repression that had led to his own imprisonment). Instead he ran for Congress from Indiana's Fifth Congressional District and got 17 percent, a distant second behind incumbent Democrat Ralph W. Moss, but narrowly edging out the Republican.
For President that year the Socialists nominated Allan Benson.
https://en.wikipedia.org/wiki/Allan_L._Benson He had gained some fame by doing the later Ludlow Amendment
https://en.wikipedia.org/wiki/Ludlow_Amendment one better--he not only wanted a national referendum to decide on war but proposed that whoever voted yes in such a referendum would be the first to be drafted to fight if war came! (So much for the secret ballot. Even as staunch an antiwar Socialist as Morris Hillquit called the idea "perfectly wild.") Anyway, the problem with Benson's attempt to run as the peace candidate in 1916 was the perception that Wilson "kept us out of war" and the worries that the Republican Party would get the US into the war--worries that stemmed less from the Republican nominee Charles Evans Hughes than from the influence Theodore Roosevelt and other war hawks might have on a Republican administration. Moreover, Wilson moved to the left on economic issues, supporting for example the Adamson Act (providing an eight hour day for railroad workers) which Hughes opposed.
https://en.wikipedia.org/wiki/Adamson_Act
The result is that a considerable number of 1912 Debs supporters voted for Wilson in 1916. They included such prominent Socialists as Algie Simons
https://en.wikipedia.org/wiki/Algie_Martin_Simons and Gustavus Myers
https://en.wikipedia.org/wiki/Gustavus_Myers (Both Simons and Myers supported the war when the US got into it in 1917 and both of them left the SP--and so did Benson.) John Reed, editor of *The Masses* though still not a member of the party nevertheless wrote the SP's national office that "I am going to vote for Wilson, because the only real principles he has (few enough) are on our side...I'm not a believer in anything lasting coming out of purely political action, but I don't want this country to become a hell for the next four years." Even twenty-five years later, long-time Socialist journalist and organizer Oscar Ameringer
https://en.wikipedia.org/wiki/Oscar_Ameringer showed some sympathy for Socialists who had voted for Wilson as the "lesser evil": "I didn't blame them for voting for Wilson. Neither they nor the American people at large wanted this country mixed up in the slaughterfest 3,000 miles across the pond. After all, the cooperative commonwealth was still a few years off, while war was already pounding at the gates."
https://books.google.com/books?id=MnflBgAAQBAJ&pg=PA171 "The cash-strapped SP spent less than $12,000 on the 1916 presidential campaign, compared to $72,000 in 1912, and received only five individual contributions over $100."
https://books.google.com/books?id=MnflBgAAQBAJ&pg=PA172 Benson did campaign seriously and attracted a respectable crowd to Madison Square Garden, but ended up with only 590,524 votes compared to Debs' 901,551 in 1912.
Was the SP's fall-off inevitable? Ross thinks that it was not, and that the SP could have done much better than Benson: "The more qualified James Maurer,
https://en.wikipedia.org/wiki/James_H._Maurer with his distinction in the labor movement and joined by the evangelistic Kate Richards O'Hare,
https://en.wikipedia.org/wiki/Kate_Richards_O%27Hare could have likely matched if not exceeded the Socialist vote of 1912." (Ross does not mention her advocacy of racial segregation--read
https://www.marxists.org/history/usa/parties/spusa/1912/0325-ohare-niggerequality.pdf if you have a strong stomach--but if anything that would probably be a net plus for the ticket in 1916. Ironically, the pioneer African American Socialists A. Philip Randolph and Chandler Owen praised O'Hare when she went to prison in 1918 for opposing the war; an editorial in *The Messenger* said she was being punished for "showing the farmers how to stop the blood sucking speculators from robbing them of the fruits of their labor."
https://books.google.com/books?id=0hAheHmTGscC&pg=PA268 Maybe Randolph and Owen were ignorant of her racial views; maybe they just thought them irrelevant in this context.)
Now I don't really know how much better a Maurer-O'Hare ticket would do in 1916 than the SP's OTL ticket. The "vote for Wilson to keep us out of war" appeal might have depressed the Socialist vote regardless of who the Socialists nominated. But consider this: Even though the number of voters in California increased substantially from 1912 to 1916, the Socialist vote in the state declined from 79,291 for Debs in 1912
https://en.wikipedia.org/wiki/United_States_presidential_election_in_California,_1912 to 42,898 for Benson in 1916
https://en.wikipedia.org/wiki/United_States_presidential_election_in_California,_1916 Wilson carried California in 1916 by less than four thousand votes. To prevent Wilson from carrying California--and therefore the Electoral College--Maurer need not have done as well in the state as Debs did. He would just have to get a few thousand more votes than Benson did...