The death of United States Supreme Court Justice Antonin Scalia has reverberated throughout American politics. All GOP presidential candidates have used his passing to underscore the need to put a Republican in the White House. The Republican congressional leadership agrees, insisting not only that President Barack Obama should not nominate a candidate, but they will not participate in the nomination process, even though that means ignoring the Constitution. This disregard for their constitutional responsibilities is striking and sets a dangerous precedent.

Article II, Section 2, Clause 2 of the U.S. Constitution says that the president "shall nominate ... judges of the Supreme Court," but he will do so "by and with the advice and consent of the Senate." Neither duty is optional: Both the president and the Senate "shall," or must, play their part.

It was something of a surprise, then, when only hours after the death of Scalia, Senate Majority Leader Mitch McConnell, the top Republican in Congress, declared that no Obama nominee would be approved before the presidential election. There would be no hearings, no vote not even consultations with Obama's nominee. McConnell's position, quickly picked up by fellow Republicans, was that a Supreme Court nomination was too important for an outgoing president. Instead, they would wait until after the November elections to let voters have their say.