WASHINGTON — (CNN) President Barack Obama on Friday used his last press conference of 2015 to defend his administration’s strategy against ISIS in the wake of terrorist attacks in California and Paris, as well as highlight policy achievements from the year, including negotiations with Cuba and Iran, action on climate change and more people signing up for health insurance under the Affordable Care Act.

“I said at the beginning of this year that interesting stuff happens in the fourth quarter, and we are only halfway through,” Obama said.

The end-of-the-year press conference is a time-honored task for Obama, which he often completes with grudging humor in the White House briefing room before beginning a long vacation in Hawaii. On his way to Oahu, Obama will be stopping Friday evening in San Bernardino, California, where a radicalized Muslim couple killed 14 people earlier this month.

Obama touted progress against against ISIS, citing U.S. air strikes in Iraq and Syria, which he said was hitting the group harder than ever, and pledged to continue to take out the group’s leaders, commanders and forces. ISIS has lost 40% of the area it once held in Iraq and is losing ground in Syria, the President said.

“As we keep up the pressure, our air campaign will continue to hit ISIL harder than ever,” Obama added, using another acronym for the terror group.

Obama also took a jab at Russian President Vladimir Putin, saying he had predicted that the Russian operation in Syria would not change the shape of the battlefield between Moscow-backed President Bashar al-Assad and his internal foes.

“I do think you have seen from the Russians that after a couple of months they are not really moving the needle that much,” Obama said.

“Of course, that is what I suggested would happen,” he said. But the President added that eventually Assad would have to go for the bloodletting in Syria’s vicious civil war to end. He said, however, that he hoped it would be possible to build a diplomatic “bridge” on the timing of his departure so that backers of Assad like Russia and Iran would feel their interests were protected.

At home, Obama acknowledged that the government could not stop all potential strikes in advance and said Americans need to remain vigilant.

“It is very difficult for us to detect lone wolf plots or plots involving a husband and wife, in this case, because despite the incredible vigilance of our law enforcement and homeland security, it’s not that different from us trying to detect the next mass shooter. You don’t always see it,” he said.

There are limits, the President said, to the government’s ability to monitor private communications between individuals, including those looking to commit terror attacks against the U.S.

“If you have a private communications between two individuals, that’s harder to discern, by definition,” Obama said, emphasizing that law enforcement and intelligence professionals are “constantly monitoring” public posts, and that such probes are part of the visa review process.

But, he added, “We’re going to have to recognize that no government is going to have the capacity to read every single person’s texts or emails or social media.”

Guantanamo Bay

Obama insisted that he would use his final year to continue to try to close to war on terror camp at Guantanamo Bay, Cuba, arguing that it remained an important recruiting tool for jihadists around the world.

The detainee population at Guantanamo Bay should drop below 100 by early 2016, he said.

The President would not go as far as to say however that he would wield executive power to empty the camp full of its remaining terror suspects — and bring those who cannot be released because they are viewed as too dangerous or cannot be tried — to the U.S mainland.

He said he would wait to see if he could reach compromise with Congress on the issue.

“I’m not going to automatically assume that Congress says no,” Obama said. “I think we can make a very strong argument that it doesn’t make sense for us to be spending an extra $500 billion to have a secure setting for 70 people.”

But Obama acknowledged he faces an “uphill battle” on Capitol Hill.

Praise for Paul Ryan, John Boehner

The press conference had a different feel than some previous years, including one two years ago, when when he faced record lows in his credibility driven by a non-functional health care website. Obama’s penultimate year in office was, after all, ripe with major achievements, many of them realized after years of work by his administration. And even as antics from the campaign trail consumed more and more attention, Obama managed to stave off “lame duck” accusations by asserting executive authority and completing major diplomatic deals.

The President praised House Speaker Paul Ryan and his predecessor, John Boehner, for shepherding a massive budget deal through Congress.

“It’s important to give credit where credit is due,” he said. “John Boehner did a favor to all of us, including now-Speaker Ryan, by working with us to agree on a top-line budget framework.”

Obama also said he had a “good working relationship” with Ryan, who succeeded Boehner over the fall.

“In his interactions with me, he has been professional and reached out to tell me what he can do and what he cannot do. I think it’s a good working relationship,” Obama said. “We recognize that we disagree on a whole bunch of other stuff, and have fundamentally different visions for where we want to move the country, but perhaps, because even before he was elected he had worked on Capitol Hill, I think he is respectful of the process and respectful of how legislation works. So kudos to him as well as all the other leaders and appropriators who were involved in this process.”

But the ISIS-linked attacks prompted new doubts about Obama’s anti-terror strategy and his ability to protect Americans from harm, and have threatened to outshine the legacy-making wins he’s secured over the past 12 months.

Since the California attack, Obama has endeavored to demonstrate his administration’s capacity to tackle terrorism. He delivered a rare prime-time Oval Office address laying out his plans to battle ISIS, reaching a football-augmented audience of more than 45 million Americans.

This week, he delivered statements from the Pentagon and the National Counterterrorism Center — venues he almost never visits — and implored the Department of Homeland Security to better communicate terror threat levels to Americans.

Officials say Obama requested visa experts at the State Department to work through the holidays to scrub screening procedures after one of the San Bernardino shooters, Tashfeen Malik, avoided detection despite having already been radicalized.

But those public efforts have done little to calm the nerves of an anxious populace which now expresses little confidence the federal government can prevent the type of terrorist attack that transpired in California earlier this month. A Washington Post/ABC News poll released Thursday showed only 22% of respondents viewed the government as capable of preventing a so-called “lone wolf” attack.

In the survey tracking Americans’ views of the year’s biggest news events, Americans placed far greater importance on the massacres in Paris, San Bernardino and Charleston than the accomplishments Obama himself would rather highlight as the year comes to a close, such as:

The rapprochement with Cuba ended decades of enmity between the two nations, and even some of the original critics of the plan have conceded that improving relations was worthwhile, though plenty of opposition remains.

The Iran deal also continues to face serious opposition, but nonetheless represents a move toward workable diplomacy in the region.

And a climate agreement signed last weekend in Paris by nearly 200 nations is another step toward a climate agenda Obama hopes will form a major element of his legacy.

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