A short history of white people rigging elections
The time and place in American history during which elections, at least in the federal government, were most likely to be contested wasn’t that of the urban political machine of, say, Chicago Mayor Richard J. Daley (associated with the modern Democratic Party). It was after the Civil War, in the Reconstruction and post-Reconstruction South.
And it was the 19th-century Democrats — the conservative, post-Confederate, anti-Reconstruction and anti-black party — most often doing the rigging, and the integrated, pro–black advancement Republican Party (a generation after Lincoln) most often calling them out.
Before the Civil War, an average of only three congressional elections were challenged each cycle; after 1900, the average was four (and there were more seats in Congress to challenge). Between 1861 and 1899, though, an average of 15congressional elections were challenged every cycle; on a few occasions, 10 percent of all members of Congress faced formal challenges.
Elections in the South were disproportionately likely to be challenged, especially after 1877 (when federal troops pulled out of the last of the Southern states, signaling the end of Reconstruction and allowing white Southerners to retake the reins of local political power). In particular, congressional districts with a large black population were the most likely to see the results of their elections challenged — usually because of accusations of widespread voter intimidation and fraud.
When House elections got challenged, it generally wasn’t because the losing candidate accused black voters of engaging in the fraud and intimidation. Usually an election got challenged because the candidate who lost the official vote for a House seat argued that black voters were being systematically disenfranchised by white Democrats, both by outright voter fraud on Election Day and by campaigns of intimidation that dissuaded Republicans (especially black Republicans) from even making it to the polls. And often, a congressional panel including both Democrats and Republicans agreed that the election had been rigged.