There was no doubt about what drove voters to one candidate or the other in the presidential race.

About 4 in 10 said the economy is on the mend, but more than that said it was stagnant or getting worse more than four years after the near-collapse of 2008. The survey was conducted for The Associated Press and a group of television networks.

In the battle for the Senate, Elizabeth Warren turned Republican Scott Brown out of office in Massachusetts, and Rep. Joe Donnelly captured a seat from GOP hands in Indiana.

Deb Fischer picked up a seat for Republicans in Nebraska, defeating former Sen. Bob Kerrey.

In Maine, independent former Gov. Angus King was elected to succeed retiring GOP Sen. Olympia Snowe. He has not yet said which party he will side with, but Republicans attacked him in television advertising during the race, and Democrats rushed to his cause.

In the presidential race, Obama won in the reliably Democratic Northeast and on the West Coast. Pennsylvania was his, too, despite two late campaign stops by Romney.

Romney won most of the South as well as much of the Rocky Mountain West and Farm Belt.

The president was in Chicago as he awaited the voters’ verdict on his four years in office. He told reporters he had a concession speech as well as victory remarks prepared. He congratulated Romney on a spirited campaign. ‘‘I know his supporters are just as engaged, just as enthusiastic and working just as hard today’’ as Obama’s own, he added.

Romney reciprocated, congratulating the man who he had campaigned against for more than a year.

Earlier, he raced to Ohio and Pennsylvania for Election Day campaigning and projected confidence as he flew home to Massachusetts. ‘‘We fought to the very end, and I think that’s why we'll be successful,’’ he said, adding that he had finished writing a speech anticipating victory but nothing if the election went to his rival.

Like Obama, Vice President Joe Biden was in Chicago as he waited to find out if he was in line for a second term. Republican running mate Paul Ryan was with Romney in Boston, although he kept one eye on his campaign for re-election to the House from Wisconsin, a race he won.

The long campaign’s cost soared into the billions, much of it spent on negative ads, some harshly so.

In a months-long general election ad war that cost nearly $1 billion, Romney and Republican groups spent more than $550 million and Obama and his allies $381 million, according to organizations that track advertising.

According to the exit poll, 53 percent of voters said Obama was more in touch with people like them, compared to 43 percent for Romney.

About 60 percent said taxes should be increased, taking sides on an issue that divided the president and Romney. Obama wants to let taxes rise on upper incomes, while Romney does not.

Other than the battlegrounds, big states were virtually ignored in the final months of the campaign. Romney wrote off New York, Illinois and California, while Obama made no attempt to carry Texas, much of the South or the Rocky Mountain region other than Colorado.

There were 33 Senate seats on the ballot, 23 of them defended by Democrats and the rest by Republicans.

Democratic Rep. Chris Murphy, a Democrat, won a Connecticut seat long held by Sen. Joe Lieberman, retiring after a career that included a vice presidential spot on Al Gore’s ticket in 2000. It was Republican Linda McMahon’s second defeat in two tries, at a personal cost of $92 million.

The GOP needed a gain of three for a majority if Romney won, and four if Obama was re-elected. Neither Majority Leader Harry Reid of Nevada nor GOP leader Mitch McConnell of Kentucky was on the ballot, but each had high stakes in the outcome.

All 435 House seats were on the ballot, including five where one lawmaker ran against another as a result of once-a-decade redistricting to take population shifts into account. Democrats needed to pick up 25 seats to gain the majority they lost two years ago.