However, the political situation changed with the revelation of the sponsorship scandal, in which advertising agencies supporting the Liberal Party received grossly inflated commissions for their services. Having faced a divided conservative opposition for the past three elections, Liberals were seriously challenged by competition from the newly united Conservative Party led by Stephen Harper. The infighting between Martin and Chrétien's supporters also dogged the party. Nonetheless, by criticizing the Conservatives' social policies, the Liberals were able to draw progressive votes from the NDP which made the difference in several close races. On June 28, 2004 federal election, the Martin Liberals retained enough support to continue as the government, though they were reduced to a minority.