WASHINGTON -- His lease renewed in trying economic times, President Barack Obama claimed a second term from an incredibly divided electorate and immediately braced for daunting challenges and progress that comes only in fits and starts.

"We have fought our way back and we know in our hearts that for the United States of America, the best is yet to come," Obama said.

The same voters who gave Obama four more years in office also elected a divided Congress, sticking with the dynamic that has made it so hard for the president to advance his agenda. Democrats retained control of the Senate; Republicans kept their House majority.

It was a sweet victory Tuesday night for Obama, but nothing like the jubilant celebration in 2008, when his hope-and-change election as the nation's first black president captivated the world. This time, Obama ground it out with a stay-the-course pitch that essentially boiled down to a plea for more time to make things right and a hope that Congress will be more accommodating than in the past.

The vanquished Republican, former Massachusetts Gov. Mitt Romney, tried to set a more conciliatory tone on the way off the stage.

"At a time like this, we can't risk partisan bickering," Romney said after a campaign filled with it. "Our leaders have to reach across the aisle to do the people's work."

House Speaker John Boehner, R-Ohio, spoke of a dual mandate. "If there is a mandate, it is a mandate for both parties to find common ground and take steps together to help our economy grow and create jobs," he said.

Senate Republican Leader Mitch McConnell of Kentucky had a more harsh assessment.

"The voters have not endorsed the failures or excesses of the president's first term," McConnell said. "They have simply given him more time to finish the job they asked him to do together" with a balanced Congress.

Obama won at least 303 electoral votes to 206 for Romney, with 270 needed for victory, and had a near-sweep of the nine most hotly contested states.

But the close breakdown in the popular vote showed Americans' differences over how best to meet the nation's challenges. With more than 90 percent of precincts reporting, the popular vote went 50 percent for Obama to 48.4 percent for Romney, a businessman-turned-politician. Romney had argued that Obama failed to turn around the economy and he said it was time for a new approach that combined lower taxes and a less intrusive government.

Obama's re-election means his signature health care overhaul will endure, as will the Wall Street overhaul enacted after the economic meltdown. The drawdown of troops in Afghanistan will continue apace. With an aging roster of justices, the president probably will have at least one more nomination to the Supreme Court.

The most pressing challenges immediately ahead for the 44th president are all too familiar: an economy still baby-stepping its way toward full health; 23 million people out of work or in search of better jobs; civil war in Syria; a menacing standoff over Iran's nuclear program.

Sharp differences with Republicans in Congress on taxes, spending, deficit reduction, immigration and more await. While Republicans control the House, Democrats have at least 52 votes in the Senate and Republicans 45. One newly elected independent isn't saying which party he'll side with, and races in Montana and North Dakota were not yet called.

Votes also were being counted Wednesday in the Montana and Washington gubernatorial races.

Even before Obama gets to his second inaugural on Jan. 20, he must deal with the threatened "fiscal cliff." A combination of automatic tax increases and steep across-the-board spending cuts are set to take effect in January if Washington doesn't quickly reach a budget deal. Experts have warned that the economy could tip back into recession with an agreement.

Despite long lines at polls in many places, turnout overall looked to be down from four years ago as the president pieced together a winning coalition of women, young people, minorities and lower-income voters that reflected the country's changing demographics. Obama's superior ground organization in the most contested states was critical to his success.

Obama's victory speech - he'd written a concession, too, just in case - reflected the realities of the rough road ahead.

"By itself the recognition that we have common hopes and dreams won't end all the gridlock, or solve all our problems or substitute for the painstaking work of building consensus and making the difficult compromises needed to move this country forward," Obama said.

"But that common bond is where we must begin. Our economy is recovering. A decade of war is ending. A long campaign is now over, and whether I earned your vote or not, I have listened to you, I have learned from you and you have made me a better president."

The president said he hoped to meet with Romney and discuss how they can work together. They may have battled fiercely, he said, "but it's only because we love this country deeply."

Romney's short concession - he'd only prepared an acceptance speech - was a gracious end note after a grueling campaign.

He wished the president's family well and told subdued supporters in Boston, "I so wish that I had been able to fulfill your hopes to lead the country in a different direction, but the nation chose another leader and so Ann and I join with you to earnestly pray for him and for this great nation."

Obama won even though exit polls showed that only about 4 in 10 voters thought the economy is getting better, just one-quarter thought they're better off financially than four years ago and a little more than half think the country is on the wrong track.

But even now, four years after George W. Bush left office, voters were more likely to blame Bush than Obama for the fix they're in.

Elsewhere on the ballot, voters in Maine and Maryland became the first to approve same-sex marriage by popular vote while Washington state and Colorado legalized recreational use of marijuana.

The most expensive presidential campaign in history, at $2 billion plus, targeted people in the nine states that determined the outcome, and the two sides drenched voters there with more than a million ads, the overwhelming share of them negative.

Obama claimed at least seven of those states, most notably Ohio, seen as the big prize. He also prevailed in Iowa, New Hampshire, Colorado, Nevada, Virginia and Wisconsin. Romney got North Carolina.

Florida was too close to call Wednesday morning. The unofficial count had Obama with a 46,000-vote lead, but Florida historically has left as many as 5 percent of its votes uncounted until after Election Day.

Overall, Obama won 25 states and the District of Columbia. Romney won 24 states.

It was a more measured victory than four years ago, when Obama claimed 365 electoral votes to Arizona Sen. John McCain's 173, and won 53 percent of the popular vote.

Preliminary figures indicate fewer people participated this time. Associated Press figures showed that about 118 million people had voted in the White House race, but that number will rise as more votes are counted. In 2008, 131 million people voted, according to the Federal Election Commission.

Obama was judged by 53 percent of voters to be more in touch with people like them. More good news for him was that 6 in 10 voters said taxes should be increased, and that nearly half of voters said taxes should be increased on incomes over $250,000, as Obama has called for.

Obama's list of promises to keep includes many holdovers he was unable to deliver on in his first term, such as rolling back tax cuts for upper-income people, overhauling immigration policy and reducing federal deficits.

A second term is sure to produce turnover in his Cabinet. Treasury Secretary Timothy Geithner has made it clear he wants to leave at the end of Obama's first term but is expected to remain in the post until a successor is confirmed. Secretary of State Hillary Rodham Clinton, Obama's rival for the presidency four years ago, is ready to leave. Defense Secretary Leon Panetta isn't expected to stay on.

To the end, the presidential race was a nail-biter. About 1 in 10 voters said they'd only settled on their choice in the last few days or even on Election Day, and they were closely divided between Obama and Romney. Nearly 1 percent of voters went for Libertarian Party candidate Gary Johnson, who was on the ballot in 48 states.

In an election offering sharply different views on the role of government, voters ultimately narrowly tilted toward Obama's approach.

"We have seen growth in the economy," said 25-year-old Matt Wieczorek, a registered Republican from Cincinnati who backed the president. "Maybe not as fast as we want it to be, but Obama has made a difference and I don't want to see that growth come to an end."

Notwithstanding his victory, Obama will lead a nation with plenty of people who were ready for a change.

"The last four years have been crap," said 73-year-old Marvin Cleveland, a Romney supporter in Roseville, Minn. "Let's try something else."