Before a replacement is named? That replacement is already named. And her name is Kamala Harris. But Afghanistan is a mess. We should never have gotten in there to begin with. (Thank you, Pres. Bush.) And we shouldn't have committed more to it. (Thank you, Pres. Obama.) And we shouldn't have let a buffoon sabotage peace talks and retreat with the Taliban making today's situation worse. (Thank you, Pres. Trump.) And then poorly handling the ultimate pull-out, that was already promised and committed to by the previous administration. (Thank you, Pres. Biden.)
I don't know how you blame one president for this ... and believe me, Biden deserves blame ... without blaming them all. I didn't hear his press talk today, but I heard the previous one, and I didn't have a question about his mental competency, as @Vanimal46 is claiming. It doesn't feel or sound like a repeat of the Reagan era with a sitting president engulfed in Alzheimer's as Reagan was. But then, Alzheimer's affects people differently, as does all kinds of dementia. Time will tell. I trust (waveringly and questionably but still do more than I don't) those surrounding Biden to be a bit more forthcoming than those who surrounded Reagan were (as in, they were not at all forthcoming, as Reagan shouldn't have run for a 2nd term) but we will see.