In a commencement speech to the graduating class at the U.S. Military Academy at West Point, the president outlined his departure from what Bush had called a "distinctly American internationalism." Instead, Obama pledged to shape a new "international order" based on diplomacy and engagement.

Obama has spoken frequently about creating new alliances, and of attempts to repair the U.S. image abroad after nearly a decade in which Bush's approach was viewed with suspicion in many quarters.

Unlike Bush, who traveled to West Point in the wake of the Sept. 11, 2001, attacks to announce his American-centered approach to security, Obama on Saturday emphasized his belief in the power of those alliances.

"Yes, we are clear-eyed about the shortfalls of our international system. But America has not succeeded by stepping outside the currents of international cooperation," he said. "We have succeeded by steering those currents in the direction of liberty and justice -- so nations thrive by meeting their responsibilities, and face consequences when they don't."

In his speech -- the ninth wartime commencement in a row -- the commander in chief, who is leading two foreign wars, expressed his faith in cooperation to confront economic, military and environmental crises.

"The international order we seek is one that can resolve the challenges of our times," he said in prepared remarks. "Countering violent extremism and insurgency; stopping the spread of nuclear weapons and securing nuclear materials; combating a changing climate and sustaining global growth; helping countries feed themselves and care for their sick; preventing conflict and healing its wounds."

And yet, as he calls for global cooperation, Obama has intensified the U.S. war in Afghanistan. And his administration has repeatedly confronted the dangers of Islamic terrorism on U.S. soil, including unsuccessful attempts to down a Detroit-bound airliner and explode a car bomb in New York's Times Square.

To the men and women in the hall, many of whom are headed to Afghanistan because of the expansion of the war the president announced here six months ago, Obama pledged "the full support of a proud and grateful nation."

The president expressed confidence in the military's ability to succeed in Afghanistan. But he warned of a "tough fight" ahead as the United States helps the Afghan people rebuild civil institutions and a security system so they can battle the Taliban and other extremists on their own.

"We have brought hope to the Afghan people; now we must see that their country does not fall prey to our common enemies," Obama said. "There will be difficult days ahead. But we will adapt, we will persist, and I have no doubt that together with our Afghan and international partners, we will succeed in Afghanistan."

In Iraq, he said, the United States is "poised" to end its combat operations this summer, leaving behind "an Iraq that provides no safe haven to terrorists; a democratic Iraq that is sovereign, stable and self-reliant."

"You, and all who wear America's uniform, remain the cornerstone of our national defense and the anchor of global security," he said. "And through a period when too many of our institutions have acted irresponsibly, the American military has set a standard of service and sacrifice that is as great as any in this nation's history."

Civilians, he added, must answer the call of service as well, by securing America's economic future, educating its children and confronting the challenges of poverty and climate change. The country must always pursue what he called the "universal rights" rooted in the Constitution.

"We will promote these values above all by living them -- through our fidelity to the rule of law and our Constitution, even when it's hard; and through our commitment to forever pursue a more perfect union," he said.

Obama praised the cadets' pursuit of being "soldier-scholars" and lauded the records of academic excellence the Class of 2010 has set. He also noted that the class's top two graduates are women, reflecting, the "indispensable role" that women play in the modern military.

"Here, in the quiet of these hills, you have come together to prepare for the most difficult tests of our time," Obama said. "You signed up knowing your service would send you into harm's way, and did so long after the first drums of war were sounded. In you we see the commitment of our country, and timeless virtues that have served our nation well."