The presidential election of 1896 brought about a major change in American politics. After this election, American presidential politics became less class-based and the Republican Party came to dominate presidential politics until the Great Depression.
The 1896 election was presented to the voters as a choice between the Free Silver Democrats (trying to represent the underprivileged farmers and workers) against the Republicans and the gold standard. The Democrats tried to paint the Republicans as the party of the wealthy few. This did not work and McKinley defeated Bryan very decisively.
After this, politics became much less class-based and the Republicans dominated the presidency until the Depression.