WASHINGTON • The Republican Party's incoherent response to the Supreme Court vacancy is a partisan reflex in search of a justifying principle. The multiplicity of Republican rationalizations for their refusal to even consider Merrick Garland radiates insincerity. Republicans instantly responded to Antonin Scalia's death by proclaiming that no nominee, however admirable in temperament, intellect and experience, would be accorded a hearing. They say their obduracy is right because: Because they have a right to be obdurate, there being no explicit constitutional proscription against this. Or because President Obama's demonstrated contempt for the Constitution's explicit text and for implicit constitutional manners...