During the 2020 campaign, then-candidates Joe Biden and Kamala Harris both expressed at least some concern about Trump rushing a vaccine to market, despite the shots being critical to their own approach to the coronavirus. Had they kept up that line of critique while Trump touted shots, Republicans could easily have been persuaded to take ownership of the vaccines.

That’s not the only counterfactual to consider: What if the people trying to influence Trump on his pandemic response had appealed more to his vanity? President Biden’s recent qualified praise of Trump on the vaccines has clearly had an impact on the ex-president. And his early approach to the virus was more malleable than we now remember it: He elevated Anthony Fauci, presided over economic restrictions that are now unthinkable (he turned against state-level lockdowns, but did not begin as an opponent), and was not as ideological as many of his supporters despite a clear preference for reopening as quickly as possible. Fauci himself played this game until Trump’s re-election prospects seemed unlikely. Could it have been played better?

In fact, if Trump had focused on vaccines rather than the 2020 election, it’s likely Biden would have enlisted the 45th president in outreach efforts earlier and less equivocally. Jan. 6 obviously made this more difficult.