Speaking on NBC’s “Meet the Press,” Senator John McCain signaled that he would no longer hold up his former colleague Chuck Hagel’s nomination after Congress returns. “I don’t believe he is qualified,” Mr. McCain said. “But I don’t believe that we should hold up his nomination any further because I think it’s a reasonable amount of time to have questions answered.”

McCain’s answer does more to sum up what’s wrong with partisanship, comity, and how senators treat national security than any other recent comment. When a cabinet nominee comes before the Senate, senators should consider any number of factors. Before deference to the president’s choice, friendship, or consideration of that nominee’s past or present statements, one question should be considered disqualifying, and that is the question of competence.

What McCain is, in effect, saying is that he has no personal or professional problem with putting an incompetent man in charge not only of America’s defense but also—because of what falls under the Pentagon’s umbrella—most of America’s intelligence assets as well.

McCain prides himself on being a maverick. How sad it is that in the twilight of his great career, McCain now is so willing to knowingly undercut U.S. national security. How reassuring it must be to Kim Jong-un in North Korea, Sayyed Hassan Nasrallah in Lebanon, and Ali Khamenei in Iran that McCain is so willing to help install an unqualified Defense Secretary. The only questions now is not whether the will test the United States, but when and how many U.S. serviceman will die because of it.