Republicans are suddenly racing to defend a seat in Kansas, where Democrats are trying to win a Senate race for the first time in nearly a century.

© David Robert Elliott for The New York Times

Candidates in three of the races that could determine control of the Senate engaged in bitter and personal attacks.

© Pool photo by Paul Sancya

The last two midterms where Democrats surged against an unpopular Republican president were in 2006 and 2018. They had notably different outcomes.

© Doug Mills/The New York Times