Nonpartisan economists credit Mr. Obama’s 2009 stimulus, along with moves by the Federal Reserve, with playing a central role in preventing the financial crisis from turning into another depression. But the president and his advisers consistently underestimated the economy’s lingering problems in 2010 and 2011. Although Republicans blocked many steps Mr. Obama wanted to take, the administration also chose to do less than it might have in several areas, especially housing.

Recession

–October 2008 campaign speech in Toledo, Ohio

“We need to pass an economic rescue plan for the middle class ... provide relief to families and communities, and help struggling homeowners. It's a plan that begins with one word that's on everyone's mind, and it's spelled J-O-B-S.”

In his most significant domestic accomplishment, Mr. Obama and his allies succeeded where previous presidents and Congressional leaders had failed and passed a sweeping health care bill. The legislation is projected to reduce the number of uninsured Americans by tens of millions, largely by subsidizing poor and middle-class families. The law also tries to reduce the growth rate of health costs, the main cause of future budget deficits. But the cost-control measures do not go as far as many experts advocate and their efficacy remains unclear.

Health care

–October 2008 presidential debate in Nashville

"If you don't have health insurance, you're going to be able to buy the same kind of insurance that Senator McCain and I enjoy as federal employees. Because there's a huge pool, we can drop the costs. And nobody will be excluded for pre-existing conditions, which is a huge problem."

Mr. Obama has cracked down on illegal immigration, deporting more than 1.5 million people during his first term. In 2012, he took executive action to allow young illegal immigrants who came to the United States as children to remain. After promising—and failing—to deliver an overhaul of the immigration laws early in his first term, Mr. Obama said the issue would be a top priority in the first year of his second term.

Immigration

–May 2008 interview with Jorge Ramos of Univision

"I cannot guarantee that it is going to be in the first 100 days. But what I can guarantee is that we will have in the first year an immigration bill that I strongly support and that I'm promoting. And I want to move that forward as quickly as possible."

Despite promising to make climate a central part of his presidency, Mr. Obama failed to persuade the Senate to pass a sweeping bill, and some Congressional Democrats were frustrated he did not push harder. The administration has financed alternative-energy programs and tightened automobile and other energy standards, contributing to a slowdown in carbon emissions.

Climate

–June 2008 Democratic nomination acceptance speech in St. Paul

"I am absolutely certain that generations from now, we will be able to look back and tell our children that this was the moment ... when the rise of the oceans began to slow and our planet began to heal."

Mr. Obama has wound down the war in Iraq, as promised. In Afghanistan, he initially sent more troops, before later reversing course and settling on a much smaller presence there. In the process, he has frustrated critics on both sides: those who believe the United States should still have a stronger presence in Afghanistan and those who believe Mr. Obama should have withdrawn more quickly. In a signature accomplishment, he ordered the raid that killed Osama bin Laden in Pakistan.

Wars

–September 2008 presidential debate in Oxford, Miss.

“We should end this war responsibly. We should do it in phases ... We cannot separate Afghanistan from Iraq, because what our commanders have said is we don't have the troops right now to deal with Afghanistan. So I would send two to three additional brigades to Afghanistan."

President Obama has changed the tax code significantly, with the aim of fighting inequality. He and Congressional Democrats eliminated the Bush tax cuts on couples' income above $450,000 (compromising from their preferred $250,000 threshold). The health care overhaul also raises taxes on the affluent. Still, he has been unable to accomplish all of his goals, and tax rates on top incomes remain far below their levels from the 1940s through 1980.

Inequality

–February 2008 interview with The New York Times