From a Washington Post column by Matt Bai headlined “How Joe Biden should solve the Kamala Harris Conundrum”:

President Biden’s main vulnerability in a reelection campaign may not be his age. It’s not his lagging approval ratings or the slowing economy, either.

No, the issue Democrats should be worried about now (and one at which Republicans have already started hammering) is succession, and I don’t mean Logan Roy’s. It’s the uncomfortable question of whether voters can get their heads around Biden’s vice president as a potential president — a question that is probably more pressing for Biden, who would be 82 if he takes the oath for a second time, than it has been for any nominee since Franklin D. Roosevelt sought a fourth term.