Biden is not senile, dummy!
He's performed his packed filled job well, and democrats appreciate that, whole heartedly. He's gotten more legislation through that democrats have wanted since FDR and Johnson....and he's handled one natural disaster after another, and ONE foreign crisis after another, and united us back with our Allies, which gives us strength again, instead of allying with Russia, and other high profile dictator friends of Trump....he also brought decency, and the norms of govt back....
The issue is some democrats believe he may be too old for another full 4 years of all of this hard work and madness of being President....
Others think, if he wears down in two years, then that is why we elect presidents and vice presidents on the same ticket.