President Barack Obama's second term was supposed to be a crowning opportunity to make his mark on the world stage, but instead he's leading an intense effort to redefine his foreign policy record - and the odds look stacked against him.
An administration-wide public relations blitz, which Obama launched with a big foreign policy speech this week, has done little to quell critics who frequently pan his global approach as rudderless, as the White House lurches from crisis to crisis.
With just two and a half years left in office, Obama's chances of forging a successful foreign-policy legacy by the end of his presidency face seemingly intractable challenges, ranging from Ukraine to Syria to the South China Sea.
While Obama has outlined a strategy that includes both a strong military and the diplomatic tools of alliances and sanctions to provide global leadership, it is unclear if he and his aides have the vision - let alone time - to change the perception of a presidency with eroding global influence.
"This is a risk-averse president who is unlikely to take bold strokes," said Aaron David Miller, a former Middle East adviser to Republican and Democratic administrations. "And he faces a series of problems in which quick-and-easy American fixes are really not available."
Topping the list is Ukraine, where Obama and other Western leaders were powerless to prevent Russia's seizure of Crimea. It was a sharp rebuke to Obama's "reset" of relations with Moscow in his first term - once seen as a big legacy achievement - and prompted Republican critics to call him naïve for ever trusting Russian President Vladimir Putin.
The best outcome Obama can hope for may be for Moscow to refrain from taking over more of eastern Ukraine, which might be a credit to the impact of U.S.-led sanctions but hardly an accomplishment of historic proportions for his second term.
The image of Obama as a passive world leader has been fed by perceptions he has allowed the civil war in Syria to fester. His failure to strike Syrian forces last year after they crossed a U.S. "red line" on the use of chemical weapons left doubts about Obama's willingness to use force in other world crises.
Though Obama used his speech to graduating cadets at West Point on Wednesday to announce increased support for Syrian rebels, he made clear U.S. involvement would remain limited.
How far Obama will go in response to China's growing assertiveness in maritime disputes with its neighbors is another tough question for the remainder of his term.
Though he offered assurances on Wednesday about his effort to deepen U.S. engagement with Asia, progress has been slow and some allies are wondering whether his Asia "pivot" is real.
Most promising of Obama's foreign policy initiatives - and the one that could go the farthest in making history - is his outreach to Iran that led to resumption of nuclear talks last year. But Obama acknowledged the odds for success are long. And even if a deal is reached, he would face an uphill struggle to win U.S. congressional approval as well as backing from Israel.
Obama's speech grew out of the president and his aides' exasperation over accusations that he had weakened America's leadership in the world, and their fear that the critique was hardening into conventional wisdom.
He may have made the situation worse when, pressed to lay out an "Obama doctrine" on a trip to Asia last month, he testily outlined a foreign policy that "avoids errors."
"Don't do stupid stuff" is the cleaned-up version of a phrase used in Obama's inner circle, aides say, to describe what they see as a pragmatic approach by a president who met his promise to extract the United States from an unpopular war in Iraq and is winding down the war in Afghanistan.
Wednesday's speech kicked off a weeks-long effort by the White House to counter critics. He plans to elaborate during a trip to Europe next week, and aides will make issue-specific speeches at home and abroad to reinforce Obama's message.
Obama, a trained constitutional lawyer, methodically defended his record and cast his critics as out of step with war-weary Americans. Some fellow Democrats and once-supportive columnists also recently have struck a more critical tone.
The speech was widely panned by newspaper editorialists, with The New York Times declaring: "The address did not match the hype, was largely uninspiring, lacked strategic sweep and is unlikely to quiet his detractors, on the right or the left."
But Michael O'Hanlon, a foreign policy expert at the Brookings Institution think tank, said Obama was striking the right balance in crises like Ukraine, though he needed to do a better job explaining himself. "A little dose of Ronald Reagan might help," he wrote in Foreign Affairs magazine.
Getting America out of Iraq and on the way to withdrawal from Afghanistan - not to mention giving the order for the mission that killed Osama bin Laden - will certainly go down as first-term bright spots that will aid Obama's overall record.
The international arena is where second-term presidents often focus more attention, especially when a divided Congress stymies their legislative ambitions. This raises the possibility that Obama may make another try at Israeli-Palestinian peacemaking after the collapse of the latest U.S. effort, or possibly make fresh overtures to communist Cuba.
But Obama's window may close before he can score new successes that might help him recover his footing. Lame-duck status is looming as this year's mid-term U.S. congressional elections approach, and world leaders may be less apt to cooperate if they see his power ebbing at home.
On top of that, recent polls show that at least half of Americans disapprove of his overall approach to world affairs,
Other second-term presidents have overcome early troubles and seen their foreign policy records treated well by historians. Reagan's second term was damaged by the Iran-Contra scandal but he is now hailed for nuclear arms control and tough diplomacy that eventually ended the Cold War.
Bill Clinton's record was tarnished by a weak response to Rwanda's genocide in his first term but his deeper engagement in Balkans peacemaking and even a ambitious but failed Middle East peace effort left him in good stead at the end of his tenure.
On the other hand, George W. Bush's public approval ratings never recovered in his second term as Americans soured on the Iraq war
© 2015 Thomson/Reuters. All rights reserved.