President Barack Obama, accompanied by Defense Secretary Leon Panetta, left, Army Chief of Staff Gen. Raymond T. Odierno, and other officials, announced a strategy shift towards Asia and said budget issues will require more restrained use of military force. (Haraz N. Ghanbari/AP)

As President Obama stood on the podium in the Pentagon briefing room Thursday to outline the nation’s defense priorities, the military stood with him. Their primary audience was a few miles across the Potomac River — in Congress.

Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, whose beloved Army will face a significant troop reduction under Obama’s plan, was at the president’s side. Marine Corps Commandant Gen. James F. Amos, whose service will also shrink, stood just behind him. And over Obama’s right shoulder loomed Gen. Raymond T. Odierno, the former commander in Iraq who is now chief of staff of the Army.

“Many of us met repeatedly — asking tough questions, challenging our assumptions, making hard choices,” Obama said. “And we’ve come together today around an approach that will keep our nation safe and our military the finest in the world.”

For a president denounced by Republican rivals as a weak and irresponsible commander in chief, the show of military support represented a political windfall for Obama as he begins campaigning in earnest for a second term.

But it also marked an evolution in Obama’s practice of Washington politics. It is evidence that, after being outmaneuvered by congressional Republicans several times, he does not intend to make the same mistakes in an election year.

By enlisting the military’s help in defining its strategic priorities, Obama has sought to ensure that he has the military’s support when his defense budget goes before Congress, including the committees led by some of his toughest Republican critics. Military leaders, in turn, now have reason to believe that Obama will not agree to more cuts.

The eight-page strategy document outlines the country’s changing military priorities after a decade of war and enshrines as policy the drone killings and other methods that Obama has relied on during his term. More than any speech he has delivered, the review places Obama’s distinctive mark on the direction of the military.

The document — and the process that created it — also sends an unmistakable message to Congress as the threat of automatic budget cuts looms: Obama and the military leadership agree on the size, scope and mission of the armed forces in a new age of austerity. The White House wasted no time in turning the spotlight on Congress, using polite language that amounted to a dare.

“The challenge will be on Capitol Hill,” said Thomas E. Donilon, Obama’s national security adviser. “It will be challenging to maintain the unified nature of the strategy through the congressional budget process.”

Under the Budget Control Act, signed by Obama in August as part of a hard-won deal with Congress to lift the borrowing limit, the Pentagon budget must be reduced by about $487 billion in the next decade, a roughly 8 percent decrease.

But under a process known as sequestration, that figure could double if Obama and Congress fail by the end of the year to cut an additional $1.2 trillion in government spending in the next decade.

Defense Secretary Leon E. Panetta and military commanders have warned in apocalyptic terms that such reductions would gut the armed forces. Obama has cast himself as a fully committed ally, behaving as if the worst-case scenario does not exist.

“The executive branch is totally ignoring sequestration,” said a senior administration official concerned about the military’s predicament who was not authorized to speak for attribution. “We are making no preparations at all.”

Some Republicans on Capitol Hill criticized Obama’s set of strategic priorities, suggesting that defense spending cuts, even those required by last year’s budget act, are unnecessary.

In a statement, Rep. Howard P. “Buck” McKeon (R-Calif.), chairman of the House Armed Services Committee, said “an honest and valid strategy for national defense can’t be founded on the premise that we must do more with less or less with less.” McKeon, who voted for the Budget Control Act last year, said Obama’s view is “founded on hope and a hollow force.”

A strategic rationale

Over four months in the fall, Obama held a half-dozen meetings with uniformed military commanders, service secretaries and the National Security Council. The sessions featured Obama as professor in chief, the hybrid role that has become the hallmark of his behind-closed-doors leadership style.

The objective was to ensure that the expected cuts would remain consistent with the country’s changing national security priorities, and to build a strategic rationale to defend those choices as a package on Capitol Hill.

“It will provide a benchmark for understanding the impact of changes” to the defense budget, Dempsey said in an e-mail, referring to the review. “Without a strategic benchmark, it would be impossible to assess the impact of future cuts.”

On each side of the river, an experienced Washington hand managed the process at Obama’s direction: Donilon, seasoned in foreign policy and electoral politics, at the White House; and Panetta, a former Office of Management and Budget director and House budget committee chairman, at the Pentagon.

“We are sensitive to the fact that this is an election year,” said one senior military official, who spoke on the condition of anonymity to discuss the process. “No one wants to be a shill for anyone. And yet this was an astonishingly open and positive collaborative process. Somehow, Panetta made it happen.”

On Sept. 7, during his weekly meeting with Panetta, Obama said he wanted to devote a substantial amount of time to the strategic review.

Donilon convened Panetta, White House budget director Jacob J. Lew and Adm. Mike Mullen, then at the end of his tenure as chairman of the Joint Chiefs, a week later at the White House. The meeting was to come up with some specific choices to present to Obama to manage the impending cuts.

“We’re going to have to do this at some point as a country,” Obama told them two days later at the first meeting with his civilian advisers and commanders. “Let’s do it now.”

This session was held Sept. 16 in the Situation Room and featured Panetta walking Obama through some of the budget-cutting ideas discussed in the earlier planning session.

“[Obama’s] impressions of the presentation were that, while thorough, it felt too much like a budget exercise,” Donilon recalled. “And he did not want this to be a mathematical set of cuts to meet a budget goal.”

Obama favored what Donilon described as a broad discussion of U.S. strategy and priorities, including the need to expand its military influence in Asia.

Civilian advisers and military leaders discussed whether the armed forces needed to continue expensive preparation to fight large, sustained counterinsurgency efforts, such as the recently concluded war in Iraq. Everything was on the table.

“It’s important to note that the work on the strategy was accelerated by the budget decisions, but not motivated by the budget,” Dempsey said.

‘Uniform buy-in’

Donilon prepared a 50-page briefing book for Obama and the other participants for an Oct. 20 meeting, providing a history of the choices under consideration and an assessment of what challenges the military would face going forward under various scenarios. It also presented a draft of the strategy whose rough outlines had emerged in the first meeting.

The book was the basis for a Nov. 2 session that Obama convened in the Cabinet Room. It included Panetta, Donilon, Dempsey and for the first time the civilian service secretaries.

Obama delivered opening remarks that emphasized the importance of the country’s economic strength in promoting its national security. He spelled out his views about the military strategy in Asia and the Middle East, the importance of caring for returning veterans, the need to bolster cyberwarfare capabilities, special operations forces, intelligence gathering and other elements that would emerge in the document.

In the Situation Room on Nov. 29, Obama wanted to know what practical results would flow from the strategy he had outlined.

This included determining the appropriate size of the forces, what technological capabilities were required and what effect, in terms of reductions, would ground forces experience.

At one point, participants said, Obama ruled out a proposal to cut an aircraft carrier group, arguing that reducing the number from 11 would undermine his ambitions in the Pacific and in the Persian Gulf, where Arab allies fear a rising Iran.

The discussion carried over into an unusual meeting Dec. 1, held in the East Room of the White House.

Obama convened not only his senior military leadership, with whom he had been working all along, but also combatant commanders from around the world and posted at the Pentagon.

The group sat around a set of tables arranged in a square with Obama on one side, flanked by Donilon and Lew.

He explained his views, and then, in the next 90 minutes, listened as his commanders commented on the emerging strategy.

“He was testing his strategy principles, and things were flagged in the process that made the result better,” one participant said. “But this was also a chance for uniformed commanders to get their shot at the president. The result of this, of course, is uniform buy-in.”

The process — inclusive and long — represented a change for the Pentagon.

As defense secretary, Donald H. Rumsfeld sought to ram his change agenda through the Pentagon’s bureaucracy with mixed results. His successor, Robert M. Gates, often relied on a group of trusted aides as he developed policy.

Panetta, who does not have as clear an agenda for changing the military, has focused more on reaching consensus rather than driving the Pentagon bureaucracy toward a particular outcome.

“Rumsfeld ran things on fear. Gates kept things to himself,” the senior military official said. “Panetta has been very collaborative.”

‘Restore that balance’

On Dec. 8, Obama convened the NSC in the Situation Room to discuss the review and its results.

The goal was to outline the principles that had emerged from the review and, in Donilon’s words, to decide “how we communicate these decisions around the world and how we coordinate these decisions around the world.”

Less than a month later, Obama headed to the Pentagon, where he became the first president to speak from the building’s briefing room. With his senior officers and months of debate behind him, Obama addressed Congress without referring to it specifically.

“It will be easy to take issue with a particular change,” said Obama, citing President Dwight D. Eisenhower’s warning to “maintain balance in and among national programs.”

Obama continued: “After a decade of war, and as we rebuild the sources of our strength at home and abroad, it’s time to restore that balance.”