Voters were headed to the polls Tuesday in a midterm election that will test whether this year's cascade of caustic political ads, fueled in part by an unprecedented deluge of outside spending, will help power a historic realignment of Congress.
Republicans expressed confidence that an electorate weary of the gloomy economy would hand them back control of the House and perhaps the Senate. The GOP needs to win 39 more seats to gain control of the House, a number that appeared easily within its reach as the party's allies dumped millions of dollars in the last week into some districts once thought to be safe for Democrats.
Still, Democrats held out hope that their vaunted get-out-the-vote operations would stem a GOP takeover; party operatives and volunteers were dispatched to contact millions of voters in the final hours before the polls opened. The Democratic National Committee said it would spend $66 million before the end of Tuesday on field efforts and advertising, logging more than 72 million voter contacts in the last six months.
Organizing for America, the group that grew out of Obama's campaign, said it knocked on 1.3 million doors on Saturday alone. Unions also mobilized their troops on behalf of Democrats.
But such efforts did not go unanswered. The Republican National Committee said it reached out to 41 million voters, aided by a bumper crop of well-funded outside groups.
American Crossroads, a group co-founded by GOP strategist Karl Rove, armed 50 canvassers with iPads to help them locate targeted voters in Nevada, where Republican Sharron Angle was hoping to defeat Senate Majority Leader Harry Reid. An additional 50 volunteers were dispatched to Colorado, and the organization spent hundreds of thousands of dollars to staff phone banks in Washington state. In all, it aimed to reach 10 million voters.
Those efforts may begin to pay off at 6 a.m. EDT, when the first votes can be cast on the East Coast, and conclude 18 hours later, when polls close in Hawaii. Weather isn't expected to be a factor, with showers and storms forecast only in the Gulf Coast.
On Monday, political analyst Charlie Cook predicted the GOP would gain a history-making 50 to 60 seats in the House, perhaps surpassing its gain of 54 seats in the so-called Republican revolution of 1994.
The landscape was not as grim for Democrats in the Senate. Political observers expect the GOP to fall short of the 10 seats necessary to gain control of the upper chamber. Senate races in Pennsylvania and Kentucky are expected to be early indicators of GOP strength.
"I think we don't get the majority back, but we come awfully close. And we finish the job in 2012," Sen. John Cornyn (R- Texas), who heads GOP Senate campaigns, predicted on NBC.
Several Senate contests may not be decided until late Tuesday or even later in the week, including those in Illinois, Colorado, Washington and the three-way race in Alaska. Many key races remained too close to call in several states, including Nevada, where First Lady Michelle Obama rallied Monday for Reid.
There, she asked voters to be more patient and to send President Obama's allies back to Washington. "My husband can't do this alone," she said.
It remains to be seen how turnout will be affected by the bombardment of ads in the final weeks. This year's TV ads were more negative than those in other recent elections, according to a new analysis by the Wesleyan Media Project. Since Sept. 1, 50% of Democratic television ads and 56% of Republican ads have attacked their opponents — the highest level in a decade, according to the project, which is analyzing every campaign spot airing this year.
Some of the advertising flood is coming too late to matter: More than 16 million ballots have already been cast through early and absentee voting across the country, according to an estimate by George Mason University professor Michael McDonald. That's the highest for any midterm election, though short of presidential year totals.
Political experts also cautioned that much of the spending could amount to an oversaturation in some districts, blunting its effect.
But strategists on both sides agreed that this cycle's massive campaign expenditures — on track to total $4 billion — widened the field of play, largely to the advantage of Republicans. While the Democrats began the year with a financial edge, in part because of their incumbent status, third-party groups backing the GOP rushed to fill that void in the final two months, outspending pro-Democratic groups roughly 2 to 1.
"I suspect there are going to be a number of very close races, and in those kind of races, last-minute money can make a big difference," said Democratic strategist Harold Ickes, who helped lead robust independent fundraising campaigns in 2004 and believes Democrats need to launch stronger fundraising initiatives for 2012. "My view is, I'm all in favor of small money. But when you're in a fistfight, you need all the help you can get."
Spending by outside groups was so potent in some districts, it exceeded Democratic fundraising advantages built over two years of incumbency.
After raising $500,000 more than Republican challenger Mick Mulvaney, Rep. John M. Spratt Jr. of South Carolina could not keep up with the third-party money flowing into his district. Spratt had raised $1.8 million this election cycle, but outside groups spent nearly $2.2 million on attacks against the powerful House Budget Committee chairman. Spratt's seat is now considered a tossup by the Cook Political Report, a respected political handicapper.
Efforts by Democrats' allies picked up steam in the final weeks, and by the last lap, spending records were being broken across the country. In New York's 20th Congressional District, Democratic Rep. Scott Murphy and his GOP opponent, Chris Gibson, had spent $11.4 million through mid-October, according to the Center for Responsive Politics. In Virginia's mostly rural 5th District, the battle over Democratic Rep. Tom Perriello's seat was headed toward $10 million, thanks to a flood of spending on both sides.
In Senate contests, Democratic candidates in the 11 most competitive races were bombarded with a combined $57.7 million worth of attacks from outside groups, compared to $46.5 million in attacks against Republican candidates.
Colorado and Pennsylvania remained the largest magnets for non-candidate spending. The four Senate candidates in those races have each fielded $10 million of attack ads launched against them by outside groups, according to tabulations by the Center for Responsive Politics.
Kathleen Hennessey, Lisa Mascaro, Michael A. Memoli and James Oliphant of the Washington bureau and Times staff writer Ashley Powers in Nevada contributed to this report.