A sharp drop in turnout, a wave of voter unhappiness with both parties and a geographically favorable slate of Senate races combined to give the GOP the advantage it needed to pull off an unexpectedly strong victory Tuesday night, according to exit polls conducted for the Associated Press and television networks.

Disdain toward both parties dominated.

The vast majority of voters had a negative view of one or both parties and about either President Barack Obama or Republican leaders in Congress. Where those groups overlapped — among voters who had an unfavorable opinion of both Democrats and Republicans (17 percent) and those who were dissatisfied or angry with both the Obama administration and Republicans in Congress (28 percent) — Republicans gained a clear advantage. These voters favored Republican candidates by about a 2-to-1 margin.

These groups took negative views on two key issues, too. Three-quarters of those who were unhappy with both Obama and Republican leadership felt that the economy is getting worse or is already bad and stagnating. Two-thirds of them said the 2010 health care law went too far. They were more likely to feel anger towards Obama than GOP leaders, 38 percent to 25 percent.

Among those who said they had an unfavorable view of both parties, pessimism reigned. Eight in 10 said the country is on the wrong track, two-thirds said life will be worse for the next generation. Seven in 10 think the government is doing too many things better left to businesses and individuals.

Across eight states — Colorado, Florida, Iowa, Michigan, North Carolina, Ohio and Virginia — that are typically competitive or Democratic-leaning in presidential election years, yet where the GOP had strong performances Tuesday, the same pattern emerged. Majorities expressed generally unfavorable views of each party.

In the five states in this group with Senate races, 58 percent said they were angry or dissatisfied with the Obama administration and 63 percent felt that way about the Republican leaders in Congress. Colorado voters were most apt to express dissatisfaction with both, 37 percent, and these voters broke by a 3-to-1 margin in Gardner’s favor.

Here’s a look at how turnout and discontent combined to produce a big night for Republicans:

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WHO DID COSTLY TURNOUT OPERATIONS REACH?

The Republican National Committee attributed much of the party’s success to its costly voter turnout program that targeted so-called “low-propensity Republican voters. “GOP officials spent millions of dollars on technology upgrades and new staff to collect data on prospective voters and ensure they cast ballots, claiming Wednesday morning that it had fundamentally changed its strategy and expanded the electorate.

The exit polls suggest partisan turnout efforts may have had equal impact in several key states. In Iowa, for example, 44 percent of voters said they had been contacted about voting for Democratic Senate nominee Bruce Braley, the exact same share said someone had reached out to them on behalf of Joni Ernst. Still, the group contacted by either campaign remains somewhat slim; 42 percent of voters said they hadn’t been contacted.

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AND THE RESULT? LOWEST TURNOUT IN DECADES

Michael McDonald, an associate professor at the University of Florida who specializes in voting rates, estimates that about 37 percent of eligible voters cast a ballot in the midterm elections, down from 41 percent in the last midterm election. If that number holds once all votes are counted, it would be the lowest turnout since 1942, when turnout during World War II dropped to 34 percent.

That can be blamed partly on Democrats losing enthusiasm. But McDonald said there are other, structural reasons. Three big states — California, New York and Texas — didn’t have a high-profile statewide race to attract voters, he said, which drove down the national figure.

“Where there are competitive elections people are voting,” McDonald said.

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SENATE STATES:

COLORADO

In Colorado, more than 6 in 10 voters said abortion should be legal in all or most cases. Yet Senator Mark Udall’s campaign, focused almost exclusively on abortion, failed to pull as much backing from supporters of his positions as Gardner drew among opponents. Among those who think abortion ought to be legal most of the time or always, 62 percent backed Udall, while 82 percent of those who say it should be illegal in all or most cases backed his Republican opponent.

IOWA

Unmarried women made up 19 percent of the electorate in Iowa, about the same as in 2012, and Braley tried to appeal to them on issues like birth control and access to legal abortions. They agreed on the issue, according to exit polls, with two-thirds saying abortion should be legal in all or most cases, yet Braley captured just 56 percent of their votes, 15 points below Obama’s support in 2012.

NORTH CAROLINA

Although men slightly outnumbered women in the electorates of some competitive states, women made up 53 percent of voters in North Carolina, about the same as in 2008. They broke for Hagan by virtually the same margin as when she won office that year. At the same time, black voters made up 21 percent of the electorate in North Carolina, similar to the 19 percent they comprised in 2008. Despite what seem like turnout successes, Hagan still lost.

VIRGINIA

Virginia voters were most likely to say they had a negative impression of both parties – 21 percent of those who voted yesterday said they viewed both negatively there, and those voters broke heavily for Republican candidate Ed Gillespie.

The Democratic incumbent, Mark Warner, may have been saved by his own likability: 56 percent had a favorable view of Warner, just 48 percent said the same about Gillespie.

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METHODOLOGY

Exit polls of voters nationally and in 27 states were conducted for AP and the television networks by Edison Research. Most interviews were conducted among randomly selected voters at a random sample of precincts nationwide and in each state. In addition, nationally and in 12 states with a high percentage of absentee or early voters, telephone polls were conducted between Oct. 24 and Nov. 2 to ensure that the views of those who voted early or absentee were reflected. Results are subject to sampling error.

(AP)