He was elected by the legislature in 1887 to the United States Senate, serving from March 4, 1887 until March 3, 1899, with repeated re-elections. Shortly after his election to the Senate, Quay outmaneuvered fellow Senator Donald Cameron to become the boss of the state Republican Party. Quay was elected as chairman of the Republican National Committee in 1888. Quay served as Benjamin Harrison's campaign manager in the 1888 presidential election. Quay's strategy focused on the state of New York, which had been the pivotal state in the previous election. Quay objected to the voting process in New York City, which had been controlled by the Democratic Tammany Hall political machine. In order to ensure that voter fraud did not occur in New York City, Quay discreetly compiled a city directory which would contain the names of all of the city's eligible voters. Although Cleveland got more votes in New York City, Harrison won New York and the presidency despite losing the national popular vote. Harrison credited "Providence" with his victory, a remark which prompted Quay to state that "Providence hadn't a damn thing to do with it."