In a commencement address at the U.S. Military Academy in West Point, New York, Obama laid out a broad approach to foreign affairs for the remainder of his presidency that shifts the fight against terrorism from Afghanistan to more diffuse threats elsewhere in the world.
Obama's tendency to rely on diplomacy and steer clear of foreign entanglements has drawn fire from opposition Republicans in Congress and various foreign policy pundits, who would prefer a more robust approach.
One of those areas is Syria. In his speech, Obama defended his decision not to intervene militarily there and expressed a willingness to expand assistance to Syrian opposition groups who are trying to oust President Bashar al-Assad.
"As president, I made a decision that we should not put American troops into the middle of this increasingly sectarian war, and I believe that is the right decision," he said. "But that does not mean we shouldn't help the Syrian people stand up against a dictator who bombs and starves his own people."
Obama said the administration would work with Congress to "ramp up" support for groups who "offer the best alternative to terrorists and brutal dictators." More resources would be given to Syrian neighbors Jordan, Lebanon, Turkey and Iraq as well.
Obama also announced plans for a $5 billion counterterrorism fund aimed at training and equipping partners in other countries to fight violent extremism.
The president on Tuesday outlined a plan to withdraw all but 9,800 American troops from Afghanistan by the end of the year and the rest by 2016, ending more than a decade of U.S. military engagement.
The president's focus on diplomacy and reluctance to use military might has prompted some foreign diplomats to bemoan privately what they regard as a lack of U.S. leadership after more than five years of the Obama presidency, much of which has been taken up with reviving a deeply troubled economy at home.
"There's an extreme indecisiveness and cautiousness that just worries people," said Senator Bob Corker, the senior Republican on the Senate Foreign Relations Committee.
"I'm not for policing the world but I do think that our lack of leadership has created a vacuum and I think that into that vacuum problems are being created," Corker said.
Obama made a strong defense of using multi-lateral institutions to address global problems. U.S. leadership helped the rest of the world isolate Russia after its intervention in Ukraine, he said, and the possibility of a breakthrough with Iran over its nuclear program - despite long odds - was real.
The president also criticized Republican leaders who cast doubt on whether climate change is real. The United States would be "out front" in forming an international framework to fight global warming next year, he said.
Obama critics fault him for not intervening in the Syrian civil war and for not being more effective at countering China's assertiveness in the South China Sea and Russia's annexation of Crimea from Ukraine.
White House officials bristle at the charges, saying Obama's critics reflexively suggest military solutions at a time when Americans are weary of war after more than a decade of costly conflict in Iraq and Afghanistan.