Biden ending his campaign is one thing; Biden *resigning* would mean:
a) endless GOP House "investigations" on Kamala Harris "covering up" Biden's mental state;
b) the GOP House and broken Senate both have to confirm the new VP, they won't, and GOP will blame Dems.
It's simply not a viable plan.
I think you basically have the same issues with Biden withdrawing; it practically invites the House GOP to ask how Biden can be fit for office, yet unable to campaign.
Also, the DC press won't care—they'll run endless "cover up" stories in either case.
That one at least has an easy answer: Biden is withdrawing from the campaign because he's fine now, but he's thinking about what he might be like four years from now. He's being a prudent steward, etc.
And I think this is basically true, that he's functioning well as president but doesn't have another 4 years in him! I mean, I'm confident that his administration will also do fine if he can't do the job, but that's not a good position to run on.
