Both Chiarelli and Petraeus have gained key backing from the Army's influential alumni, such as retired Army Gen. Barry McCaffrey, who recently briefed Bush on his views of Iraq policy, and former Army Secretary Thomas White.
"Chiarelli seems to be the voice of broadening the strategy, [that] this is more than just a shoot-'em-up war," White said in an interview. "If we're going to redo this thing, and he seems to be the advocate of change, I'd put him in charge."
Others candidates associated with the counterinsurgency group are Army Lt. Gen. Martin E. Dempsey, another former division commander in Iraq who is in charge of rebuilding the Iraqi military, and Marine Lt. Gen. James N. Mattis, commander of the 1st Marine Expeditionary Force.
Retired Army officers warned, however, that most members of the senior officer corps are more traditionally trained, focused on conventional warfare rather than asymmetric threats faced by U.S. forces in Iraq. The Army's seniority system will be a strong influence working against Petraeus and Chiarelli, both relatively junior three-star generals.
"A guy like Petraeus is so ferociously creative and brilliant, sometimes that makes the buttoned-down senior military leadership nervous," said McCaffrey. "Rumsfeld, I think, has been frightened by talented Army generals."
Under Rumsfeld, several generals seen as more conventionally minded have been given important posts in recent months, including Army Lt. Gen. Raymond T. Odierno, who replaced Chiarelli as the head of day-to-day operations in Iraq last week, and Gen. Dan K. McNeill, recently selected as the new U.S. commander in Afghanistan.
If Gates decides to go with a more conventional leader at Centcom but pass over Casey, contenders could include Army Gen. David D. McKiernan, currently in charge of Army forces in Europe.
"The Army, left to its own devices, has a senior leadership that for 30 years has carefully guarded the Army's primary mission of maintaining conventional arms proficiency," said the recently retired Army officer. "That's Odierno, but that's also the core Army ethos."
The importance of the Centcom choice is hard to overstate, current and former officials said. Although current commanders have given lip service to waging a more complex counterinsurgency campaign, mid-level officers complain privately that their success on the battlefield is still judged by conventional measures, such as the number of insurgents killed or captured.
