Mitchel was overthrown in 1917 by an even larger plurality than elected him

Evidence

When Red Mike Hylan swept into City Hall—Mitchel, who had been elected in 1913 by the largest plurality in New York’s history, was turned out in 1917 by an even larger plurality—Progressivism in the city was dead. “We have had all the reform that we want in this city for some time to come,” Hylan said, and issued an order soon after taking office in 1918: all Bureau staffers who had been working with city agencies were to be dismissed at once. — Robert A. Caro, The Power Broker, 370