The collapse of populism was marked by the Populist Party's defeat in the 1900 U.S. presidential election. After the blow, the party quickly faded away and its platforms were absorbed by other parties.
North Illinois University explains that the Populist Party was a target of the mainstream from its inception. The upper- and middle-class considered Populists ignorant reactionaries whose policies would hinder the economic growth that only laissez faire economics could achieve. Democrats in the South utilized an aggressive, racist campaign to divide whites and blacks. These forces combined against the Populists in 1896, the year in which Populists endorsed Democratic nominee William Jennings Bryan for president. Despite intense campaigning, the Populist ticket lost the election to Republican William McKinley.
This proved to be a setback from which the party never recovered. Four years later, the Populists ran their own candidate in the 1900 election. Following the poor performance, the Populist Party quickly disbanded. It reorganized briefly for the 1904 and 1908 elections, after which the party disbanded once more.
North Illinois University argues that part of the reason for the Populist Party's quick dissolution following its political losses was the fact that the two major parties adopted many of the positions of the Populists: direct election of senators, bank regulations and the federal income tax.