Much controversy has centered recently around John McCain's possible judicial nominees should he become president. In my view, a President McCain would face a difficult tradeoff between the goal of appointing conservative jurists and the goal of saving the McCain-Feingold law from invalidation by the Court.

John McCain may well be sincere in claiming that he wants to appoint conservative justices. However, he is undoubtedly even more sincere in his support of the McCain-Feingold campaign finance law, his proudest achievement as a legislator. The narrow conservative majority on the Supreme Court is not fond of McCain-Feingold and has already significantly narrowed its scope in the Wisconsin Right to Life case. The five conservatives most likely believe that McCain-Feingold is unconstitutional; that applies also to swing voter Anthony Kennedy, who voted to strike down most of McCain-Feingold in McConnell v. FEC, the 2003 decision that narrowly upheld the law by a 5-4 margin (here is Kennedy's strong dissent in that case).

If he wants to have any chance at all of saving McCain-Feingold, a President McCain will have to appoint justices committed to upholding it. As a practical matter, however, there are few if any conservative jurists who are both 1) qualified to sit on the Court, and 2) likely to vote McCain's way on campaign finance issues; I can't think of even one offhand. Almost any well-known jurist likely to vote the conservative way on federalism, property rights, abortion, and other major constitutional issues is also likely to be just as committed to striking down McCain-Feingold as the conservatives currently on the Court. Thus, McCain will be strongly tempted to appointmoderate to liberal justices or a "stealth" candidate like Justice Souter with no clear judicial philosophy. The stealth approach failed for George W. Bush when the Harriet Miers nomination blew up in his face. However, McCain might do better with it, since he would be facing a Democratic-controlled Senate rather than a Republican one.

I honestly don't know whether McCain - should he be elected - would put his desire to uphold McCain-Feingold above his campaign promises to appoint conservative justices. However, the possibility that he might appoint an analogue to Justice Souter or Harriet Miers in order to save McCain-Feingold is a very real one. This concern is only slightly assuaged by recent endorsements of McCain by conservative legal luminaries such as Ted Olson and Miguel Estrada. Perhaps they know something about McCain's plans that I don't. However, it will take a lot more evidence to convince me that McCain is genuinely willing to set his commitment to McCain-Feingold aside in making Supreme Court appointments.

Supreme Court appointments are not the only issue in the presidential election and probably not the most important. However, conservatives and libertarians who care about legal issues should be aware of the possibility that a President McCain might end up appointing justices likely to vote against their positions on most major constitutional issues before the Court. The above is not an endorsement of Mitt Romney, who has his own shortcomings. Nor is it a comprehensive rejection of McCain, whose positions on some issues I very much agree with. It does, however, flag an important concern about McCain's potential judicial appointments.