Mike Rogers, the Republican Senate nominee, has suggested that further scrutiny of the 2020 election was warranted and that voting irregularities sunk his first Senate bid two years ago.

© Brittany Greeson for The New York Times

Unable to unite behind a single candidate in Michigan’s Seventh Congressional District, moderate Democrats worry that they’ve complicated their chances in a key November battleground.

© Matt Maasdam For Congress; Nathan Layne/Reuters; William Lawrence for U.S. Congress