I think if she'd retired early enough in Obama's term, they'd have had to approve someone.  

Actually, no it would not have happened. McConnell openly said he would work to prevent Obama from seating ANY judges and certainly none on the Supreme Court. This was why Reid changed the rules to a simple minority in the Senate to appoint lower court judges in 2013 because there were a load of openings that needed to be filled but the Republicans had resorted to hyper partisanship and blocked every appointment because it was their sworn mission not to allow Obama and Democrats to seat them. McConnell of course was furious with this because Reid had a way around his blocking and so McConnell falsely blames Reid for his own power grab. McConnell is one of the central reasons why the situation got so outrageously bad and all McConnell has done is pour gasoline on the hyper partisan fire. 

Obama, and it is one of the great failings of his administration, seeing that he would be blocked from seating judges basically gave up on that. When he appointed Garland this was not done to seat a liberal judge, he intentionally chose a judge Republicans approved of as a way of showing he wanted bipartisanship but McConnell took a big steaming crap on that and told all Republicans to refuse to even meet with Garland. It was a total joke. 

Democrats need to take all this into consideration and they need to, if they regain the Senate and the presidency, fight back. I am not saying they need to create a "super liberal court" but expanding the court and filling all the seats  with whomever they want...and let's face it Biden is no progressive so if he does this it will be a bunch of moderates anyway...will take the court out of play for the sort of crazed super partisanship McConnell created. It would then be literally several decades before the court could ever be drastically altered and that would not be likely because it is not likely that any single president could appoint enough judges to remake the court because the Senate and president would be shifting every 4 to 8 years...so doing this takes this lunacy McConnell has promoted off the table. 

The Supreme Court should not by a hyper partisan body nor issue. McConnell and Trump have and continue to piss all over that and everything the court stands for. And I looked at the two woman Trump is supposedly deciding between and they are, of course, a couple of complete loons. The one McConnell has pushed swore an oath to some wacko religious group that has as one of their requirements that the wife recognizes the husband as head of the household and decisionmaker. Brilliant idea to replace a champion of women's rights with this nitwit. The other one from Florida believes completely in poll taxes and methods of voter suppression...which is probably why Trump likes her. This is why Democrats can't sit on their thumbs if they manage to get into a position to repair things...but they obviously need to have the will to fight.