Washington ? President Barack Obama sacked his loose-lipped Afghanistan commander Wednesday, a seismic shift for the military order in wartime, and chose the familiar, admired — and tightly disciplined — Gen. David Petraeus to replace him. Petraeus, architect of the Iraq war turnaround, was once again to take hands-on leadership of a troubled war effort.

President Barack Obama, accompanied by Vice President Joe Biden and Gen. David Petraeus, announces Wednesday in the Rose Garden of the White House in Washington that Petraeus would replace Gen. Stanley McChrystal as the top commander in Afghanistan.

Obama said bluntly that Gen. Stanley McChrystal’s scornful remarks about administration officials in interviews for a magazine article represent conduct that “undermines the civilian control of the military that is at the core of our democratic system.”

He fired the commander after summoning him from Afghanistan for a face to face meeting in the Oval Office and named Petraeus, the Central Command chief who was McChrystal’s direct boss, to step in.

By pairing those announcements, Obama sought to move on from the firestorm that was renewing debate over his revamped Afghanistan policy. It was meant to assure Afghans, U.S. allies and a restive American electorate that a firm hand is running the war.

Expressing praise for McChrystal yet certainty he had to go, Obama said he did not make the decision over any disagreement in policy or “out of any sense of personal insult.” Flanked by Vice President Joe Biden, Defense Secretary Robert Gates and Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, in the Rose Garden, he said: “War is bigger than any one man or woman, whether a private, a general, or a president.”

He urged the Senate to confirm Petraeus swiftly and emphasized the Afghanistan strategy he announced in December was not shifting with McChrystal’s departure.

“This is a change in personnel but it is not a change in policy,” Obama said. The president delivered the same message in a phone call to Afghan President Hamid Karzai, the White House said, and Karzai told Obama he would work toward a smooth transition.

As Obama was speaking in the Rose Garden, McChrystal released a statement saying that he resigned out of “a desire to see the mission succeed” and expressing support for the war strategy.

With lawmakers of both parties praising the choice of Petraeus, the White House is confident he will be confirmed before Congress adjourns at the end of next week.

Obama hit several grace notes about McChrystal and his service after their meeting, saying he made the decision to sack him “with considerable regret.”

And yet, he said the job in Afghanistan cannot be done now under McChrystal’s leadership, asserting that the critical remarks from the general and his inner circle in Rolling Stone displayed conduct that doesn’t live up to the standards for a command-level officer. “I welcome debate among my team, but I won’t tolerate division,” Obama said. He had delivered that same message — that there must be no more backbiting — to his full war cabinet in a Situation Room session, said a senior administration official.

The announcement came as June became the deadliest month for the U.S.-dominated international coalition in Afghanistan. NATO announced eight more international troop deaths Wednesday for a total of 76 this month, one more than in the deadliest month previously, in July 2009. Forty-six of those killed this month were Americans. The U.S. has 90,800 troops in Afghanistan.

Petraeus, who attended a formal Afghanistan war meeting at the White House on Wednesday, has had overarching responsibility for the wars in both Afghanistan and Iraq as head of Central Command. He was to vacate the Central Command post after his expected confirmation, giving Obama another key opening to fill. The Afghanistan job is actually a step down from his current post but one that filled Obama’s pre-eminent need.