Dr. Abdul El-Sayed and Representative Haley Stevens traded sharply critical comments Friday, escalating intraparty tensions in Michigan’s pivotal Senate race.

© Nic Antaya for The New York Times

Representative Haley Stevens has been less than enthusiastic about Dr. Abdul El-Sayed, injecting late intraparty tensions into a race that could decide Senate control.

© Nic Antaya for The New York Times

At rallies this weekend, Mr. Obama and Mr. Trump delivered two starkly contrasting pitches, differing in style and substance.

© Nick Hagen for The New York Times

The 44th president sharply criticized Mr. Trump, who hit back later in the day. Mr. Obama also assailed Vivek Ramaswamy, the Republican nominee for governor of Ohio.

© Victor J. Blue for The New York Times