In the Arizona battle for an open Senate seat, Representative Martha McSally, the Republican nominee, used a 15-year-old quip about the Taliban by Representative Kyrsten Sinema, the Democratic nominee, to say that Sinema is guilty of treason.

In Ohio, Representative Jim Renacci, the Republican who is trying to unseat Senator Sherrod Brown, told the editorial board of The Cincinnati Enquirer that “multiple women” had contacted him to say that they had been assaulted by Brown between 1987 and 2004. Renacci offered no names, no details, no way for anyone to look into the matter. He just dropped the bomb and moved on.

In at least four House districts around the country, Republicans twisted aspects of Democrats’ pasts for inflammatory television commercials that alleged a tolerance for terrorism or an indulgence of it.

And in one House district in Arkansas, a renegade Republican super PAC even produced a radio ad that suggested that white Democrats would be “lynching black folk again” if their party won.