Obama’s news conference in two minutes: The president took questions from reporters Tuesday, discussing Syria, the Boston bombings, closing Guantanamo, immigration reform and Jason Collins. (The Washington Post)

President Obama said Tuesday that he will revive his push to close the U.S. military prison at Guantanamo Bay, Cuba, a first-term campaign promise that a Democratic-led Congress rejected as impractical and potentially unsafe.

With a majority of Guantanamo’s 166 detainees on a mass hunger strike, Obama said at a White House news conference that the existence of the facility damages the country’s image abroad, costs too much money and undermines U.S. counterterrorism efforts by serving as a recruiting tool for militants.

“I’m going to go back at this,” he said. “I’m going to reengage with Congress to try to make the case that this is not something that’s in the best interests of the American people.”

Obama’s appearance before the media Tuesday highlighted how much his second and final term remains consumed by the unfinished business of his first.

From his policy toward Syria to health-care legislation to his inability to close the prison at Guantanamo Bay, Obama faced many of the same questions that have defined much of his time in office.

President Obama said during a press conference Tuesday that the use of chemical weapons in Syria could be a “game changer” in the U.S. response to the conflict, but he made clear his administration first needs more evidence. (The Washington Post)

He used long, sometimes defensive answers to portray himself as undaunted by the unresolved challenges yet limited in his ability to secure the changes he has sought because of his continuing confrontation with a divided Congress.

That self-assessment of his political power also is largely consistent with his message to the nation since Democrats lost control of the House in 2010. His domestic agenda has largely ground to a halt since then.

Now his window for progress in Congress is even smaller than it once was, and it may close entirely after the 2014 midterms unless his party can take control of both chambers.

It was unclear Tuesday how he intends to revive his political prospects after setbacks on gun control and fiscal negotiations to avoid across-the-board spending cuts, known as sequestration, that he acknowledged are undermining the economy.

“Rumors of my demise may be a little exaggerated at this point,” Obama said during the news conference, in a phrase reminiscent of Bill Clinton’s 1995 assertion of his own relevance after his party lost the House the previous year.

But in responding to a journalist’s assertion that he appears powerless in dealing with Congress, Obama responded, “You seem to suggest that somehow, these folks over there have no responsibilities and that my job is to somehow get them to behave.”

“That’s their job,” he said.

The news conference fell on the 100th day of what for Obama has already been a difficult second term. Last month, he lost his high-profile bid for stricter gun control after the December shootings in Newtown, Conn., that killed 20 children and six educators.

Days after that Senate defeat, the first large-scale bombing in the post-Sept. 11, 2001, era killed three and wounded more than 250 others near the finish line of the Boston Marathon.

On another issue, his administration informed Congress last week that it has “varying degrees of confidence” in evidence suggesting that chemical weapons have been used in Syria’s civil war, which has killed more than 70,000 people.

One issue that is making progress in Congress, largely without Obama’s direct help, is immigration legislation that many Republicans back as a way to bolster support among Hispanic voters.

The president said that passing an immigration overhaul would be a “historic achievement.” He also expressed optimism that recent meetings with Republican senators could lead to a budget agreement.

“There’s a genuine desire on many of their parts to move past not only sequester but Washington dysfunction,” Obama said.

Even his health-care law — the signature legislation of his presidency — remains a work in progress. Obama defended the complicated implementation process that will extend health care to the estimated 15 percent of the population that does not have it.

In assuring the public that the process is not nearly as messy as some members of Congress have portrayed it, Obama said that people who are insured will probably see no further changes as the law takes full effect. He also warned of challenges ahead.

“Even if we do everything perfectly, there will still be glitches and bumps,” Obama said.

His pledge for a renewed effort to close the prison at Guantanamo Bay comes as the hunger strike by detainees has highlighted the legal ambiguities surrounding their detention. Obama has been working to shutter the prison since the day after he took office in 2009; on Tuesday he again cited Congress as the chief obstacle.

Of the 166 detainees held at Guantanamo Bay, 100 are on a hunger strike, with 21 being force-fed, according to Lt. Col. Samuel House, a spokesman for Joint Task Force Guantanamo. House said that five of the hunger-striking detainees are being treated in a hospital at the base but that none have a life-threatening condition.

The Navy sent 40 additional medical personnel to Guantanamo Bay over the weekend in response to the increasing numbers of detainees on hunger strike. The military said the move was planned several weeks ago.

Defending the move, Obama said Tuesday, “I don’t want these individuals to die.”

According to attorneys for the detainees, the initial catalyst for the three-month-old hunger strike was newly aggressive searches by guards that involved the manhandling of Korans.

The military said all searches of Korans were conducted by Muslim cultural advisers, not by the guard force. They noted that in the past detainees have used their Korans to hide contraband.

The hunger strike has since become a wider protest against what the detainees view as the administration’s abandonment of its effort to close the facility, according to both the military and detainees’ attorneys.

About 86 detainees at Guantanamo have been cleared for transfer home or resettlement in a third country by a Justice Department-led interagency task force, but the transfers ground to a halt after Congress imposed restrictions on moving detainees.

Human rights groups praised Obama’s decision to resurrect efforts to close the military detention facility but said he already has the power to act despite congressional restrictions.

“President Obama is right to recommit to closing Guantanamo. But it’s time to do more than talk,” Zeke Johnson, director of Amnesty International USA’s Security With Human Rights Campaign, said in a statement.

Peter Finn contributed to this report.

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