 A growing number of Senate Democrats have voiced concerns about Joe Biden's prospects for re-election, especially after his poor debate performance. None have called on him to bow out of the race. But pressure is growing for the White House to address concerns that a poor Biden performance could damage down-ballot candidates as well. Among them, Democrat Senators John Tester of Montana and Sherrod Brown of Ohio. Flipping their vulnerable seats would likely allow Republicans to reclaim the Senate majority.