A presidential candidate who banked on support from the Ku Klux Klan. Blunt demands to ban certain religions and races from playing a full role in society. Violence and disorder at campaign rallies.

And a political party that tore itself apart not only over whom it would nominate for president, but also over whether religious and racial bigotry would be visible in its fabric.

Welcome to the 1924 Democratic National Convention, held at Madison Square Garden in New York, when the most powerful bloc in the Democratic Party was the Klan, fiercely opposed by the Tammany Hall Democrats. It was the longest political convention in American history, going 16 days and requiring 103 ballots before a compromise candidate was selected.

The convulsions of the Democrats in 1924 are, in broad movements, mirrored in the rived and bedraggled pilgrimage of the Republicans in 2016 as they stagger toward their convention behind Donald J. Trumpand his rivals.