ALMOST AS MUCH as President Bush's loyalty, Secretary of Defense Donald Rumsfeld may owe his job security to the prospect of what would happen if he resigned.

Sure, it's a distraction from the war in Iraq and the rest of the war on terror to have a half dozen ex-generals calling for Rumsfeld's ouster. But suppose the president named a replacement. The scene would shift to the Senate Armed Services Committee, where a confirmation hearing would give 24 U.S. senators live TV time to air all their misgivings about a war that fewer and fewer Americans continue to support.

You can see where Bush might prefer the four-star revolt to a three-ring circus.

There is, however, one man whom the American people and all senators know well enough that the president could, in effect, request a confirmation by acclamation. He happens to be a war hero. He would boost the morale of the men and women in uniform. And he would have bipartisan backing (ranging from his good pals John Kerry and Joe Lieberman to his would-be White House rivals Bill Frist and George Allen).

This not-a-mystery man is, of course, John McCain.

We know President Bush isn't big on admitting mistakes, and he surely doesn't relish the prospect of accepting Rumsfeld's resignation only to see days of media coverage rehashing all the old questions about why we went to war. But this needn't be a multi-stage drama or a mea culpa. In the same prime-time speech that he announces Rumsfeld is leaving, Bush can announce

Which, in a nutshell, is that nothing is more important to the future security and foreign policy interests of the United States than that the mission in Iraq succeed.

The president can make clear he continues to value the work Rumsfeld has done in transforming the military for the challenges of the future. He can even say history will remember the willingness to be unpopular that allowed the Defense secretary to make much-needed tough decisions.

Then the president can turn to the reasons he is asking McCain to serve his country once again: to make the Pentagon a full partner in the building of a stable, self-governing Iraq and to re-engage the American people in the importance of the pursuit.

No one can match McCain's eloquence when it comes to talking about being a part of a cause larger than oneself. That's the message Americans need to hear--and believe--if there's any hope of regaining widespread public support for the difficult work ahead in Iraq.

Okay, but what about McCain? He wants to be president, not a cabinet member. What's in it for him?

Like it or not, his political fate is already tied to what happens in Iraq. Although he's been clear in his disagreements with Rumsfeld, McCain nevertheless embraced the war as appropriate and continues to insist on success. If, say, Sen. Allen has also been a steadfast supporter of the war, many Americans don't know it simply because most Americans still don't know him. McCain (the senior senator from Meet the Press) has no such cover.