WASHINGTON — President Joe Biden on Thursday opened a critical stretch in his effort to salvage his imperiled reelection campaign, arguing the stakes extend far beyond his own political prospects to the future of the country’s economy and democracy itself.

There is a growing sense that Biden may have just days to make a persuasive case that he is fit for office before Democratic support for him evaporates in the aftermath of his disastrous debate performance last week against Republican Donald Trump.

In an interview with a Wisconsin radio station that aired Thursday, Biden said, “The stakes are really high. I know you know this. For democracy, for freedom ... our economy, they’re all on the line.”

The interview on the Earl Ingram Show on the Civic Media Radio Network, taped Wednesday, was the part of a media and public events blitz that Biden and his staff have acknowledged as a make-or-break moment. Some financial backers were holding off or canceling upcoming fundraisers, according to a person familiar with the plans who spoke on condition of anonymity.

After hosting a July Fourth barbecue at the White House for military families, Biden is scheduled to campaign in Wisconsin on Friday and sit for an interview with ABC’s George Stephanopoulos that will air as a prime-time special that night. He plans to be in Philadelphia on Sunday and hold a full news conference during the NATO summit in Washington next week.

It is not a given that his campaign will survive even that long if he does not deliver a strong showing on ABC.

But time is short for a possible change. The Democratic National Committee announced weeks ago that it would hold a virtual roll call for a formal nomination before the party’s national convention, which begins Aug. 19.

“I had a bad night. ... I screwed up,” Biden said of the debate in the radio interview.

“But 90 minutes on stage does not erase what I’ve done for 3 1/2 years,” he said in a different interview, with Philadelphia-area WURDRadio.