Former Senator Joe Manchin III of West Virginia said he told Senator Susan Collins, who is locked in a tough re-election fight, “Whenever you run again, I’m going to come.”

© Sarah Silbiger for The New York Times

Dr. Abdul El-Sayed’s campaign in Michigan released a new ad highlighting his faith, which Republicans have used to attack him in a tight Senate race.

© Zbigniew Bzdak for The New York Times