What’s the most credible argument that the current president can’t run for re-election yet can continue with the world’s toughest job for another 100 days?

Announcing both on the same day would cause anxiety? It would make sense to me if the administration is spacing those out. Doubt it’ll last 100 days.

Productising RWAfi @plumenetwork. Building https://transferagentprotocol.xyz on it. Hosting /rwa and /plume and /nest

Different time, different administration.

Nixon resigned and everything worked fine?

This is the correct answer. This and the fact that it makes no sense to do both right this minute since Harris would be going in without a VP of her own. 

My belief is he'll resign in a month or 2, after Harris officially is selected and has her VP selected.