It's a terrible argument. If the senate is not controlled by the same party as the president and they dislike the president's choice for supreme court, they can vote not to confirm him/her. It also encourages the president to choose a nominee who can appeal to both parties. McConnell refused to allow Garland to even have hearings in the Senate let alone a vote because he feared that some of his republican colleagues may have been persuaded. If there are two controlling parties in two parts of the government then the solution is compromise. This is a philosophy totally abhorrent to McConnell whose views can only be supported by an authoritarian minority.

Wait it takes two to compromise, and a Supreme Court pick is really important . What did the Democrats offer McConnell in exchange for Garland hearings?