Vulnerable Dem senator breaks silence on Biden's fitness, demands president prove ability

Sen. Jon Tester, D-Mont., said President Biden needs to prove his ability to serve a second term in the White House, joining a group of Democratic lawmakers scrutinizing the president after a lackluster debate performance last month and a sit-down interview that failed to calm concerns. 

"President Biden has got to prove to the American people—including me—that he's up to the job for another four years," Tester said in a statement Monday.

DEMOCRATS' SENATE HOPES COULD HANG ON SPLIT-TICKET VOTING COMEBACK

"Meanwhile...