This is not to say that a president never has to take the Senate into account when making his selection. Before Alito, the last two nominations to draw serious, ideologically-based opposition were also Republican appointees who would have shifted the court in a more conservative direction. In 1991, George H.W. Bush nominated Clarence Thomas to replace Thurgood Marshall. And in 1987, Ronald Reagan appointed Robert Bork to replace Lewis Powell. Both men were reviewed by Democratic-majority Senates and were widely opposed by Democrats while being overwhelmingly supported by Republicans. Bork was rejected, and Reagan countered with the much more moderate Anthony Kennedy, who was unanimously confirmed. Thomas, meanwhile, was confirmed—an outcome that, if anything, argues against a president needing to defer to an opposition minority.
In all those cases, it was the composition of the Senate at the time of the appointment—not the vagaries of what may have been said in earlier hearings—that was the controlling factor. So why do so many people believe otherwise? Well, it’s possible the rules of the political game will be different next time. Democrats tend to be less disciplined than Republicans. And court nominations in general invite more scrutiny from the opposition now—it’s hard to imagine another Clarence Thomas case, in which a Senate majority accedes to an aggressive pick by a president of the other party.
But there’s still every reason to believe that if Obama has a friendly Senate when the next vacancy occurs—and if he has the stomach to deal with Republican complaints—he’ll have a free hand to make his selection. This week’s testimony, meanwhile, will be of decidedly secondary importance. Arguing otherwise is just another attempt to assign significance to proceedings that don’t have much of it.