Democratic Resurgence.

The close electoral split between Democrats and Republicans in the years following the Civil War was altered in the elections of 1896. In that year the Republican William McKinley won the presidency with a decisive victory over agrarian Democrat William Jennings Bryan. Thereafter, the Republican Party held a majority of congressional seats for twenty-six of the thirty-four years from 1896 to 1930 and, with only two exceptions, won every presidential election from 1896 until 1932. Except for the 1910s the Republicans dominated American politics for the first third of the twentieth century. From 1910 to 1918 the Democratic Party held a majority of seats in Congress, and Democrat Woodrow Wilson won both presidential elections held during the decade.

The Republican Fracture.

The Democratic ascendancy in these years was largely the result of the split of the Republican Party into conservative and progressive (or modern liberal) wings. During...