Just four hours after former Massachusetts Gov. Mitt Romney's pragmatic decision to suspend his campaign for the Republican presidential nomination, Sen. John McCain stood before the annual Conservative Political Action Conference and asked the assembled activists to support his bid for the White House. The "maverick" acknowledged differences he has had over the years with many in the room, offered a spirited defense of his 24-year record in Congress, and made an eloquent, self-effacing appeal for conservatives to unite in the "urgent necessity of defending the values, virtues and security of free people against those who despise all that is good about us."

Reaction was swift -- and predictable. Both Sens. Clinton and Obama, locked in a slash-and-burn contest for Democratic dollars and delegates, quickly dispatched dueling news releases, each claiming dominance over the presumptive Republican nominee. Earlier in the day, Howard Dean, their party's chairman, warned that delay in choosing a standard-bearer could jeopardize Democratic hopes in November: "The idea that we can afford to have a big fight at the convention and then win the race in the next eight weeks is not a good scenario." Regrettably, some of my conservative friends seem unwilling or unable to grasp that the same applies to the GOP and appear disposed to squander an obvious advantage.

My "colleagues" in the so-called mainstream media gladly roll their cameras and recorders for those who assert that "McCain is not a real conservative" or who say, "I can never support him," and the ones claiming, "I just won't vote this year." It is, for me, a disheartening display because I have, as we say in the Marines, "been there -- done that."

After I won the 1994 Republican nomination for a U.S. Senate seat in Virginia, I naively assumed that all in the GOP would pull together behind my conservative candidacy. I clearly don't know much about politics. If I did, I'd be writing this from my U.S. Senate office instead of my home in Virginia's Blue Ridge Mountains. But at the trade school John McCain and I attended in Annapolis, Md., they did teach me how to count. I lost by a narrow margin in a three-way race. Some of those who were with me then are among those who now say they won't support John McCain.

Worse still, since this election cycle began last year, the Democrats have raised more money than the GOP, and in the primary balloting that began last month, Democrats have turned out more voters. These numbers matter because they reflect the energy and commitment of the opposing parties in this year's presidential contest.

Neither John McCain nor anyone in his campaign asked me to write this column. But I cannot sit silently while my fellow conservatives do to John McCain what GOP "moderates" did to me. Today the stakes for our country are far higher, and the implications for the future are far greater than who sits in one of 100 U.S. Senate seats. Now our nation is at war against a vicious foe. We need a president who has proved how to win it.

During the course of the past six years, I have made a dozen protracted trips to cover U.S. soldiers, sailors, airmen, guardsmen and Marines defending us against a jihad hostile to all that we hold dear. In the dark days when Iraq's Anbar province was the bloodiest place on the planet, John McCain was one of the few in Congress brave enough to venture into that cauldron. I know because I saw him there.

During those trips, he listened to bright, brave young Americans wearing flak jackets and flight suits and became a steadfast supporter of a winning strategy for ending this long and costly conflict. But the senator's commitment goes far beyond political rhetoric. One of his sons is a student at our alma mater; the other is a Marine Corps lance corporal serving in harm's way. Thanks to John McCain's vision and resolve, a few weeks ago, my cameraman and I walked in shirt sleeves down streets in Ramadi and Fallujah, where we used to dodge bullets, IEDs and RPGs.

The election in November will determine how we proceed on the most profoundly important matter confronting our nation: the crucial outcome of an unprovoked war being waged against us by radical Islam. All other issues, as important as they are, pale in comparison to achieving victory over those who seek to destroy our very way of life.

Sen. McCain has pledged to win this war. We must do so, for the consequences of failure would be staggering. But as he has acknowledged, he cannot do that without the support of conservatives who man the phone banks, raise the funds, walk the precincts and turn out the vote on Election Day. I hope my fellow conservatives will decide as I have: We need John McCain as commander in chief.