Well one main issue for the court is that, having weighed in with Roe and its successors, they can't help being still involved one way or the other now. More b

Well one main issue for the court is that, having weighed in with Roe and its successors, they can't help being still involved one way or the other now. More broadly, the ongoing total dysfunction of Congress (and/or the entire political system) has meant both parties have increasingly turned to the relatively-functional court to get their wins. The fact, at least historically, that Supreme Court precedents are seen as quite durable is another factor weighing in favor of the court's involvement. The insulating effect on the politicians is a good point, too. There's also I think the factor that both parties have found it convenient for the Supreme Court to be very powerful and involved in lots of issues just as a motivational factor for their bases: the dialogue around presidential and senatorial races now routinely revolve around Supreme Court appointments as maybe the only important issue.