Halfway through last week’s presidential debate, an uncomfortable question entered my head: Would I get into a car if President Biden were in the driver’s seat? Would I buckle a small child into a car seat behind him?

I voted for Biden in 2020. If he continues to run this year, I will vote for him again because, whatever his flaws, he hasn’t tried to overturn the results of a legitimate election. But no, after watching him repeatedly lose his train of thought midsentence, I wouldn’t let him drive me or anyone I loved to the grocery store. Like 72% of my fellow registered voters, I think he’s too old not just to run for president but also to be the president.

Anyone who’s dealt with an aging parent knows that Biden’s acuity is headed in one direction, possibly precipitously. So the world can’t afford any of the rationalizations now floating around — that his staff runs things anyway or, at worst, that if he deteriorates too much, the Cabinet can always invoke the 25th Amendment and replace him with Vice President Harris.

Passed in the wake of John F. Kennedy’s assassination, Section 4 of the 25th Amendment works well if the president is in a coma: The Cabinet and the vice president can vote to make her “acting president,” then hand that power back if and when the president recovers. However, for obvious reasons, Section 4 makes it easy for the president to reclaim his powers, which makes it ill-suited for sidelining a president who becomes impaired, but not entirely disabled. A conscious but erratic president can declare that “no inability exists,” which gives the Cabinet four days to either return power to him or refer the question to Congress.

If it’s thrown to the House and Senate, lawmakers can take up to 21 days to deliberate before voting on whether to pronounce the president “unable.” To pass, such a vote requires a two-thirds majority; otherwise the president resumes his powers. And if he loses the vote, he can restart the process by once again declaring that “no inability exists.”

If Congress sends a clear enough message, he might not bother trying again. But of course, the reason for invoking Section 4 would be that the president has started making bad decisions. More to the point, sending this message would take a lot of Democratic votes. And if his party is finding it too difficult to force him out now, consider how much more difficult it would be after he is reelected.

Mustering the necessary courage becomes even harder if Republicans control one or both houses of Congress, because making the vice president acting president leaves the speaker of the House — currently, Republican Mike Johnson — next in line for the presidency. To be appointed, a new vice president would need to be approved by a majority of both the Senate and the House. The GOP might have an effective veto.

Perhaps naively, I think Biden’s staff might invoke the 25th Amendment, despite the obstacles, if it mattered enough — if, say, China invaded Taiwan and Biden proved too foggy to negotiate the crisis. But crucial decisions would remain on hold while advisers debated whether to remove him. The mere possibility of such instability might invite strategic rivals to test us.

It’s still fair to consider these risks a lesser danger to the United States than another four years of Donald Trump (especially since Trump, at 78, is also at elevated risk of diminished capacity). This is the calculation I expect to make if Biden is still on the ballot come November. Today, though, Democratic decision-makers have time to make a better choice.