Would Biden be so determined to pack the court that he would spend precious capital early in his presidency on it? If so, voting, green energy and health care legislation would take a back seat, and depending on the severity of the backlash, perhaps not happen at all.
If, instead, all that legislation went first, court-packing would be pushed toward the back of the line, when Biden would have less political power than when he started. This would make court-packing, a gargantuan task in the best of circumstances, even harder.
The question of timing would enter in another way. Let’s say there’s a bruising battle over court-packing that Democrats win sometime in the second year of a Biden presidency. How much time and political capital would they then have to fill the seats? Enough to fill all of them before the midterms? If not, they certainly wouldn’t get filled if Republicans took back the Senate, a scenario that’s easy to imagine.
And, of course, when Republicans hold the presidency and Congress again, they’d add their own seats or subtract the Democratic ones, making the entire exercise a nullity except for the permanent diminishment of the standing of the court.