Sure, he did.
Otherwise Democrats and Republicans would be as extinct as Whigs.
How FDR Saved Capitalism
"How FDR Saved Capitalism
by
Seymour Martin Lipset,
Gary Marks
Tuesday, January 30, 2001
"With the coming of the Great Depression in the 1930s, a sharp increase in protest and anticapitalist sentiment threatened to undermine the existing political system and create new political parties.
"The findings of diverse opinion polls, as well as the electoral support given to local radical, progressive, and prolabor candidates, indicate that a large minority of Americans were ready to back social democratic proposals.
"It is significant, then, that even with the growth of class consciousness in America, no national third party was able to break the duopoly of the Democratic and Republican Parties.
"Radicals who operated within the two-party system were often able to achieve local victories, but these accomplishments never culminated in the creation of a sustainable third party or left-wing ideological movement.
"The thirties dramatically demonstrated not only the power of America’s coalitional two-party system to dissuade a national third party but also the deeply antistatist, individualistic character of its electorate."