WASHINGTON - It was supposed to be a joke. "Are you still president?" comedian Stephen Colbert asked Barack Obama earlier this month.

But the question seemed to speak to growing weariness with the president and skepticism that anything will change in Washington during his final two years in office. Democrats already are checking out Obama's potential successors. Emboldened Republicans are trying to push aside his agenda in favor of their own.

At times this year, Obama seemed ready to move on as well. He rebelled against the White House security "bubble," telling his Secret Service detail to give him more space. He chafed at being sidelined by his party during midterm elections and having to adjust his agenda to fit the political interests of vulnerable Democrats who lost anyway.

Yet the election that was a disaster for the president's party may have had a rejuvenating effect on Obama. The morning after the midterms, Obama told senior aides, "If I see you moping, you will answer to me."

People close to Obama say he is energized at not having to worry about helping - or hurting - Democrats in another congressional election on his watch. He has become more comfortable with his executive powers, moving unilaterally on immigration, Internet neutrality and climate change in the last two months. And he sees legacy-building opportunities on the international stage, from an elusive nuclear deal with Iran to normalizing relations with Cuba after a half-century freeze.

"He gained some clarity for the next two years that is liberating," said Jay Carney, who served as Obama's press secretary until this spring. "He doesn't have as much responsibility for others."

Still, pillars of Obama's second-term agenda - gun control, raising the federal minimum wage, universal pre-school- seem destined to stand unfulfilled. Wrapping up the Iraq and Afghanistan wars isn't turning out to be nearly the tidy success story Obama once envisioned. Even supporters say one of the president's top remaining priorities may have to be simply preventing Republicans from dismantling his earlier accomplishments, including the health care law.

The Yes-We-Can man is entering a twilight of maybes, his presidency still driven by high ambitions but his power to achieve them running out.

Before the midterm election results arrived, Obama's advisers say, the president realized he would finish his presidency with Republicans running Capitol Hill.

Whatever message the Democrats' defeat sent about the president's own standing, Obama concluded the status quo meant more gridlock.

Indeed, 2014 had been another year of fits and starts for a White House that has struggled to find its footing in Obama's second term.

The feeble HealthCare.gov website stabilized, but scandal enveloped the Department of Veterans Affairs. Syria got rid of its chemical weapons, but a violent extremist group pulled the U.S. back into military conflict in the Middle East. The unemployment rate fell, but so did Obama's approval ratings - to the lowest levels of his presidency, worse than the second-term averages for most recent presidents.

"I don't care who you are, after eight years or six years of the presidency, your influence has eroded," said Robert Dallek, a historian who has met periodically with Obama. "Even someone like Eisenhower or Reagan, you just can't sustain it."

While White House officials acknowledge the presidency has challenges in its waning years, they say recent economic gains and executive actions on immigration and climate change show Obama still can exert considerable influence.

"This year the president's policy successes vastly outstripped his political successes," said Dan Pfeiffer, a senior White House adviser.

Nearly two dozen White House officials, former Obama aides, presidential historians and political analysts discussed Obama's standing as he closes his sixth year in office, some on the condition of anonymity because they were not authorized to publicly discuss their conversations with the president or his top advisers.

For much of the year, Obama appeared to struggle with the realization that his political standing had slipped.

He publicly complained about criticism of his foreign policy by pundits in Washington and New York (his private gripes were more colorful and profane). Despite Democratic pleas to stay out of November's elections, he said his policies were indeed on the ballot. He desperately sought to break free of the confines of the White House.

One afternoon in June, he joined his chief of staff in making an impromptu Starbucks run on foot, leaving aides and reporters sprinting to catch up.

"Bear on the loose," the president's advisers jokingly said. They said it was good for his mood to break free from the bubble.

But there were also real concerns in the West Wing about his behavior. Not only was he trying to escape the ever-present press, but Obama was ordering his Secret Service detail to keep its distance.

In 2014, Obama also went back to war in the Middle East. Less than three years after the last American troops left Iraq, Obama sent U.S. forces back to train and assist the country's security forces in fighting Islamic State extremists. By fall, the U.S. was launching airstrikes against the militants in Iraq and Syria.

As he announced the strikes, Obama promised Americans this time would be different from the long wars in Iraq and Afghanistan. No U.S. combat troops would on the ground, he said.

But he seemed to be trying to reassure himself as much as anyone else.

In public and in private, Obama appears to understand his presidency may end on a war footing. He's been reading "Redeployment," a collection of short stories about the Iraq war by former Marine Phil Klay. Shortly before Christmas, he made an unusual visit to a military base in New Jersey to thank troops and their families - and pledge to preserve hard-fought military gains abroad.