When Roberts has an ideological or jurisprudential position to impress into law, he is likely to wait for the time at which it is politically palatable.
There is much to be said in favor of a supermajority rule for confirming Supreme Court Justices. As Mike Rappaport and I argue in the Judicial Filibuster, the Median Senator and the Countermajoritarian Difficulty, the result of such a rule will be more moderate justices, less likely to go to any extremes. At a more theoretical level, a supermajority rule will temper the countermajoritarian difficulty — the problem created by an unelected judiciary invalidating the decisions of the popularly elected branches. Judicial review under this confirmation rule would be more likely to impose the long-term limitations on popular government that most people themselves desire.
The filibuster, however, is a weak supermajority rule, because a partisan majority of Senators can change it any time through the so-called nuclear option. Despite my preference for a supermajority confirmation rule, the filibuster is unlikely to survive, if Senator Chuck Schumer has implied, the Democrats are inclined to filibuster Trump’s Supreme Court nominees. Noah Feldman is thus wrong in claiming that it is plausible that the Supreme Court will continue to operate with only eight members.
First, the filibuster for Supreme Court confirmations has been gravely weakened by the previous Democratic controlled Senate’s elimination of the filibuster for other nominations, both for the executive branch and for the lower federal courts. That act showed that Democrats would get rid of the filibuster when it was expedient to do so. Indeed, when Clinton seemed likely to win, many Democrats were openly talking about getting rid of the filibuster for the Scalia vacancy. A decision by the Republican Senators to retain it only to have Democrats toss it in the future would make them look like chumps.
Second, the stakes of the Scalia vacancy are very high given that a Democratic appointee would change the median justice from Anthony Kennedy to Stephen Breyer. The possible transformation of the Court underscores the fear of each party that the other would get rid of the filibuster if necessary to fill this seat.
Third, as Mike and I have noted, moderate Senators would like to maintain the filibuster, because it tends to make the nominee more moderate. But with party polarization, there are few Senators in the middle.
It is possible that the Republican Senate would tolerate the filibuster of the first nominee, but it inconceivable that it would let the Democrats filibuster a second. Trump will appoint Scalia’s successor.
The weakness of the filibuster underscores the advantages of constitutional entrenchment. If supermajority rule is wise, as I believe it is for Supreme Court confirmations, an optimal constitution would include the rule within its structure. That rule would actually force compromise because it could not be changed by ordinary politics.