Senator Jon Tester, Facing Tough Re-Election Fight, Urges Biden to Drop Out

Senator Jon Tester of Montana called on President Biden to drop his campaign for re-election on Thursday night, becoming the second sitting Democratic senator to publicly join the effort to push Mr. Biden out of the race.

“I have worked with President Biden when it has made Montana stronger, and I’ve never been afraid to stand up to him when he is wrong,” Mr. Tester, a vulnerable incumbent whose opponent has sought to tie him tightly to Mr. Biden, said in a statement. “And while I appreciate his commitment to public service and our country, I believe President Biden should not seek re-election to another term.”

Mr. Tester’s Washington office said he was also endorsing an open process to select the nominee at the Democratic National Convention, rather than throwing his support behind Vice President Kamala Harris.

Mr. Tester is locked in a tight re-election race of his own, and he needs all the distance from Mr. Biden he can get in his deep-red state. Even before Mr. Biden’s poor debate performance last month put the spotlight back on his age and mental acuity, Mr. Tester had kept him at arm’s length while working to appear bipartisan and appeal to moderate and Republican voters.

Mr. Tester is just the second Democratic senator to call on Mr. Biden to quit, though a group of House Democrats have done so and other senators have been said to be pushing Mr. Biden to the exits behind the scenes.

Last month, when Mr. Tester debated Tim Sheehy, a former Navy SEAL and businessman who is his Republican rival for the Senate seat, he criticized the Biden administration’s energy policies and its approach toward immigration. “The bottom line is: He doesn’t listen to me enough,” Mr. Tester said of Mr. Biden. “He needs to.”

But Mr. Sheehy