There's a 40% chance President Joe Biden will not seek reelection, according to Stifel.
Brian Gardner, the firm's chief Washington policy strategist, is out with a research note that calls it a "make or break week" for the president's campaign as Congress returns from its Fourth of July recess.
"There's a 60% chance, more likely than not, that he's going to stay in," Gardner told CNBC's "Fast Money" on Monday. "Biden loves to prove the smart kids in the Democratic Party wrong. So, the more he hears voices from the elites that he needs to get out, the more he digs in his heels."
Gardner, who advises equity analysts on how White House policy could affect their coverage areas, thinks Democrats who are urging Biden to drop out face a considerable obstacle.
"They lack leverage. They can try to persuade Mr. Biden to drop out of the race, but they cannot force him out," Gardner told clients on Monday. "It is a fantasy to think that at least half of Mr. Biden's most dedicated supporters will turn on him and not vote to nominate him."
While concerns about the president's age have persisted throughout his latest bid for the Oval Office, a poor debate performance in June has changed the tenor of the conversation. Polling data and financial markets are starting to reflect a shift in sentiment that favors former President Donald Trump.
If Biden stays in the race, however, Gardner contends the Democratic Party may still see a favorable outcome.
"There's a certain level of voter that is just never going to vote for Donald Trump no matter what," Gardner said.