President Bush's decision to elevate General David Petraeus to lead the Central Command is not only an act of courage, it may prove to be transformative in the global war on terror, and even in the 2008 election. God has apparently seen fit to give the U.S. Army a great general in this time of need, a simple fact which President Bush has had the sense to recognize and act on. Bush's action comes not a moment too soon, and given Petraeus's ability, perhaps not too late either.

Why do I rank Petraeus so high? When it comes to military strategy, I defer to others (including several who write for this magazine) to put his generalship in its larger historical context. To all but the willful and the blind, though, the swiftness of the turnaround in Iraq is indisputable. And to anyone who has had even a worm's eye view of the U.S. Army and its bureaucratic tendencies, it is not just indisputable but astounding.

I was a lowly 24-year-old draftee, a specialist fourth class, stationed with an American advisory team to a South Vietnamese infantry division in the Mekong Delta when the Tet offensive happened in February 1968. As is now well known, American and South Vietnamese units fought well, and the enemy was dealt a devastating blow in military terms. But the U.S. Army had a commanding general, William Westmoreland, who had no clue what had happened.

We then had about 540,000 soldiers in South Vietnam. Westmoreland flew to Washington and demanded that President Johnson send an additional 206,000. By doing so, he terminated his own prospects of success in Vietnam and also those of Johnson, who within a month announced his decision not to seek reelection. West-moreland's visible panic dealt a devastating blow to home-front support for the war at a moment when the enemy had just been badly depleted on the battlefield. This is what a reactive, bureaucratic commander is capable of accomplishing in a single month.

Petraeus is the polar opposite of Westmoreland, and for that matter the generals who preceded him in command of our forces in Iraq. From the moment he arrived, greater risk and greater accountability were demanded of our troops, which they gladly gave because they sensed he had a plan and knew exactly what he was doing.

As originally reported in the press, the emphasis on living in the neighborhoods and mingling with Iraqis had a touchy-feely overtone, making even some hawks wonder if Petraeus was leaving our soldiers needlessly vulnerable. But the move to the neigh-borhoods had a predominantly military aim, which was reliable intelligence about Al Qaeda in Iraq and its fellow-travelers.

The move worked and the intelligence flowed because Petraeus was correct in sensing that the jihadists' power over the locals stemmed not from sympathy but from fear. Once the Iraqis started telling our forces where the enemy was, the jihadists saw their safe havens swiftly disappear, and Petraeus's troops became a killing machine. That is why the levels of violence in Sunni Iraq declined so swiftly. The Sadrists and other Iranian-backed Shiite militiamen are well aware of the fate of the Sunni jihadists and will be deeply affected by it, whether Petraeus or his superb deputy and successor, General Raymond Odierno, is in command when the final crunch comes.