A defiant President Joe Biden vowed Wednesday to keep running for reelection, rejecting growing pressure from Democrats to withdraw after a disastrous debate performance raised questions about his readiness. But in ominous signs for the president, a second Democratic lawmaker called on Biden to exit the race while a leading ally publicly suggested how the party might choose someone else.

“Let me say this as clearly as I possibly can as simply and straightforward as I can: I am running … no one’s pushing me out,” Biden said on a call with staffers from his reelection campaign. “I’m not leaving. I’m in this race to the end and we’re going to win.”

But despite his efforts to pull multiple levers — whether it was his impromptu appearance with campaign aides, private conversations with senior lawmakers, a weekend blitz of travel and a network television interview — to salvage his faltering reelection, Biden was confronting serious and mounting signs that support for him was rapidly eroding on Capitol Hill and among other allies.

Rep. Raúl Grijalva, D–Ariz., told The New York Times that while he backs Biden as long as he is a candidate, this “is an opportunity to look elsewhere” and what Biden “needs to do is shoulder the responsibility for keeping that seat — and part of that responsibility is to get out of this race.”

Meanwhile, Rep. Jim Clyburn, a longtime Biden friend and confidant, said he would back a “mini–primary” in the run–up to the Democratic National Convention next month if Biden were to leave the race. Clyburn, a South Carolina Democrat, floated an idea that appeared to be laying the groundwork for alternatives by delegates during the Democrats’ planned virtual roll call that is scheduled before the more formal party convention, which is set to begin Aug. 19 in Chicago.

On CNN, Clyburn said Vice President Kamala Harris, governors and others could join the competition. “It would be fair to everybody. … Because if she were to be the nominee we need to have a running mate. And need a strong running mate.”

Clyburn, a senior lawmaker who is a former member of his party’s House leadership team, said he has not personally seen the president act as he did on the debate stage last week and called it “concerning.”