Casey's approach had emphasized efforts to build up Iraqi troops so U.S. forces could begin to draw down. Under Petraeus, U.S. forces have focused on trying to reduce the sectarian violence that has overwhelmed Iraq and on trying to improve security for the Iraqi people, the core tenet of the counterinsurgency manual.
'A good communicator'
Petraeus' arrival in Baghdad involved more than just a change in military strategy.
Casey had paid little attention to the American public's view of the war while he was commanding from Baghdad. He had little love for congressional testimony or press interviews. Some Army officials believe Casey's distaste for the spotlight contributed to an erosion of the public's understanding of U.S. goals in Iraq.
Petraeus is more comfortable communicating with the public, and views it as an important responsibility. As commander, Petraeus has sat for many long interviews with journalists and regularly takes them with him as he travels around Iraq.
"He is a good communicator," said a senior administration official who served with Petraeus. "He is equally comfortable talking to soldiers or talking on national television."
Experienced in the ways of Washington, Petraeus understood there were other, less direct ways to communicate his ideas. Since he has taken command in Baghdad, a parade of think-tank experts and other scholars have traveled to Iraq to advise the military and get an up-close view of the war. And Petraeus has brought experts who have agreed with him and those who have been critical.
Stephen Biddle, a fellow at the Council of Foreign Relations, had made some favorable remarks about the buildup strategy but had written critically about Petraeus' counterinsurgency manual and the training of the Iraqi security forces. So Biddle was surprised to find himself invited to Baghdad for a month to help advise the military command.
"It's very unusual among Army generals to invite a known critic to give you advice," Biddle said.
Biddle was invited to spend a month in Iraq as part of the Joint Strategic Assessment Team. Other scholars associated with Washington think tanks were invited on weeklong trips to visit Iraq and talk with Petraeus. Although those visits helped the military hear outside perspectives, they were also an opportunity for the military to ensure that its view of the war was understood.
"One of the interesting things about Petraeus is he is much more politically sophisticated," said one scholar who has advised Petraeus. "He understands not only that he needs advice, but that advice-givers are part of a community that develops the general conventional wisdom on the war."
Two of the scholars who visited Iraq, Kenneth M. Pollack and Michael E. O'Hanlon of the Brookings Institution, wrote a newspaper op-ed after their visit expressing a measure of optimism for Petraeus' strategy -- and were criticized for succumbing to military propaganda.
Biddle said he believed that by bringing in outside experts, Petraeus was simply trying to help foster an informed debate, not execute a snow job.
"This is a guy trying to do good government," Biddle said.
An optimist by nature
Even before he has spoken, Petraeus' appearance in Washington on Monday has been criticized by Democrats. Lawmakers opposed to the troop buildup have linked Petraeus to Bush and questioned the accuracy of some of the information that the military in Baghdad has released.
Aides to Petraeus and to Bush have sought to emphasize the Iraq commander's independence from the White House. Although Petraeus gave his recommendation to Bush, the general's aides have not provided his prepared testimony to the White House.
Still, by his nature Petraeus is an optimist, and his version of a balanced assessment could strike opponents of the current strategy as overly positive. Besides, there is little doubt that Petraeus and Bush are on the same page. The two men have spoken weekly about Iraq and the general's views about the strategy.
"All those encounters do lead to something," said the senior administration official. "And it could be a fairly common perspective."
(BEGIN TEXT OF INFOBOX) David Howell Petraeus
Born: Nov. 7, 1952.
1974: Graduates from the U.S. Military Academy at West Point.
1983: Gen. George C. Marshall Award winner as the top graduate at the U.S. Army Command and General Staff College.
1987: Earns doctorate in International Relations from Princeton University.
1991: During a training exercise, Petraeus is shot in the chest. The bullet just misses his heart.
2000: Petraeus breaks his pelvis in a sky-diving accident.
2001 to 2002: Petraeus serves 10 months in Bosnia, helping command the NATO mission.
2003 to 2004: Leads the 101st Airborne Division during U.S. invasion of Iraq. His division is later assigned to Mosul, where Petraeus develops counter-insurgency theories.
June 2004 to September 2005: Oversees the training of the Iraqi military.
October 2005 to January 2007: Serves as commanding general, Combined Arms Center at Ft. Leavenworth, overseeing production of the Army's Counterinsurgency Field Manual.
February 2007: Takes charge of the Multi-National Force -- Iraq, following nomination by President Bush and confirmation by the Senate, becoming the top U.S. commander in Iraq.
Source: Times research