Please answer a question about the following article about The Bronx:

The Bronx has often shown striking differences from other boroughs in elections for Mayor. The only Republican to carry the Bronx since 1914 was Fiorello La Guardia in 1933, 1937 and 1941 (and in the latter two elections, only because his 30-32% vote on the American Labor Party line was added to 22-23% as a Republican). The Bronx was thus the only borough not carried by the successful Republican re-election campaigns of Mayors Rudolph Giuliani in 1997 and Michael Bloomberg in 2005. The anti-war Socialist campaign of Morris Hillquit in the 1917 mayoral election won over 31% of the Bronx's vote, putting him second and well ahead of the 20% won by the incumbent pro-war Fusion Mayor John P. Mitchel, who came in second (ahead of Hillquit) everywhere else and outpolled Hillquit city-wide by 23.2% to 21.7%.

What party was Hillquit?
Socialist