WASHINGTON (AP) — President Joe Biden is opening a critical stretch in his effort to salvage his imperiled reelection campaign. There’s a growing sense that Biden may have just days to make a persuasive case that he’s fit for office before Democratic support for him completely evaporates in the aftermath of his disastrous debate performance against Donald Trump. Already, some financial backers are holding off or canceling upcoming fundraisers. And Biden himself acknowledged to Democratic governors that he needs to get more sleep and limit late events so he can be fit and rested for the job.