Republicans seized control of the U.S. Senate on Tuesday, so the next two years will be marked either by the bipartisan cooperation promised Wednesday by President Obama and likely Majority Leader Mitch McConnell or by more gridlock. Note: With all votes counted in Alaska, the Republican leads but the incumbent has not conceded. The Virginia race is too close to call, and a Dec. 6 runoff will decide Louisiana's.

Alaska

Dan Sullivan, Republican

Sullivan, 49, who won his first run for office, ran an upbeat campaign on optimism and grand ideas that resonated with Alaskans. His opponent, incumbent Sen. Mark Begich, portrayed Sullivan as an outsider, but Republicans made the race a referendum on President Obama.

Alaskan roots are important to the state's voters, and Sullivan — who was born in Ohio — often boasted that his wife is from the state.

He also highlighted his work on energy and national security issues and his efforts to combat domestic violence. Sullivan, a U.S. Marine infantry officer who deployed overseas after the Sept. 11 terrorist attacks, served in the Bush administration as an assistant secretary of state under Secretary Condoleezza Rice. He was Alaska's attorney general and commissioner of the state Department of Natural Resources.

Arkansas

Tom Cotton, Republican

Cotton, 37, who was elected to the U.S. House in 2012, targeted Democratic Sen. Mark Pryor as one of Obama's closest allies, but had to defend his own votes against the farm bill and federal disaster aid.

Cotton promised to repeal the Affordable Care Act and suggested that the Islamic State in Iraq and the Levant is working Mexican drug cartels. He is a foreign policy hawk who may clash with Republican peers.

He replaced a retiring Democrat in Congress and during his 19 months on Capitol Hill earned solid conservative credentials.

Colorado

Cory Gardner, Republican

Gardner, 40, a fifth-generation Coloradan, got his start at his family's farm equipment dealership and was elected to the U.S. House in 2005. A fiscal conservative, he wants to cut taxes and signed a pledge agreeing never to raise them.

He's also a social conservative who opposes emergency contraception. Reproductive rights was a top issue in his campaign against Democratic Sen. Mark Udall. When the incumbent attacked Gardner for his opposition to abortion, the challenger ran ads saying birth control should be available over the counter.

Georgia

David Perdue, Republican

Political newcomer Perdue, 64, has family links to Georgia politics: His cousin Sonny Perdue was a former governor.

He campaigned on his record as a business executive at Reebok and Dollar General Corp. He was respected in the business world for turning around troubled businesses — a record that his Democratic opponent, Michelle Nunn, used to depict him as a heartless, outsourcing millionaire.

A fiscal hawk, Perdue won a crowded primary by campaigning against "career politicians" and by calling the federal debt the biggest threat to national security. He supports a "fair tax" that would replace income, estate and employment taxes with a single levy on consumption.

Iowa

Joni Ernst, Republican

Ernst, 44, will be the first woman to represent Iowa in the U.S. Senate. She gained national attention with a viral TV ad in which she boasted about her pig castration skills, but her folksy appeal and military record also fueled her win for an open seat against Democratic U.S. Rep. Bruce Braley.

Democrats depicted her as "the next Sarah Palin," but Ernst won the men's vote by a 16-point margin and split women's votes with Braley. Visits from Michelle Obama and Bill and Hillary Clinton couldn't save him.

Her campaign theme was "mother, soldier, leader" — a reference to her rank as a lieutenant colonel in the Iowa Army National Guard. She served in Kuwait and as a company commander in the Iraq war.

Michigan

Gary Peters, Democrat

Peters, 56, gave Democrats a rare U.S. Senate victory with a solid win over Republican nominee Terri Lynn Land.

Peters, a three-term congressman, was confident enough in the campaign's final days to become the only Democratic U.S. Senate nominee to welcome President Obama for a rally.

The race between Land and Peters was the most expensive in Michigan history, with much of the spending coming from outside groups.

Before being elected to Congress in 2008, Peters served in the U.S. Navy Reserve and spent 22 years as an investment adviser. He lost a 2002 race for Michigan attorney general and was appointed commissioner of the Michigan Lottery.

Montana

Steve Daines, Republican

Daines, 52, who was elected to the U.S. House in 2012, emphasized his support for the Keystone XL pipeline and gun rights, but also reminded voters that he voted for the Violence Against Women Act.

Although he was born in California, he claimed that he's a fifth-generation Montanan, prompting some Democrats to demand that he produce his birth certificate during the campaign. He said his parents moved to California just before he was born and returned to Montana when he was a small child.

In 1984, Daines was one of the youngest delegates at the 1984 Republican National Convention, and he says he's a big fan of Ronald Reagan.

He spent 13 years with Procter & Gamble in the U.S., Hong Kong and China.

Nebraska

Ben Sasse, Republican

Sasse, 42, is the president of Midland University in his hometown of Fremont. He dominated a four-candidate field to win the seat held by Mike Johanns, a Republican who is retiring.

Sasse's percentage of the vote Tuesday — 65 — and his margin of victory were the largest in an open-seat election in Nebraska since 1978.

Sasse courted Tea Party support and was endorsed by such conservatives as Sarah Palin and says he hopes to help instill a new sense of leadership among Senate Republicans built around the concept of an ­American renewal.

North Carolina

Thom Tillis, Republican

Tillis, 54, the speaker of the North Carolina House, narrowly defeated Democratic Sen. Kay Hagan after tying her to Obama's initiatives.

In the Legislature, he passed budget cuts that curtailed education funding and rejected the federal Medicaid expansion that limited access to insurance in the state. He reduced unemployment benefits and helped pass a voter ID law.

Tillis kept a promise that he would serve only four terms in the Legislature and instead entered the crowded primary for a chance to run against Hagan, who was seeking a second term.

He skipped four candidate forums in an effort to avoid lesser-known rivals, but debated the major Republican candidates and was endorsed by former Florida Gov. Jeb Bush.

Oklahoma

James Lankford, Republican

Lankford, 46, is considered the fastest-rising star in recent Oklahoma history.

He was a political unknown in 2010 when he beat veteran state lawmakers for a seat in the U.S. House.

On Tuesday, he beat a Democratic state senator who called for criminal justice reform and legalizing marijuana, and an independent.

Lankford, a former Baptist youth camp director, already has a high profile in Washington. He served on a committee that investigated the killings of Americans in Benghazi, Libya, and IRS scrutiny of conservative groups seeking tax-free status.

He said that his priorities in the Senate will be slowing spending, encouraging economic growth and fighting limits on faith.

South Dakota

Mike Rounds, Republican

Like most of his fellow Senate newcomers, Rounds' campaign in a four-way race took hold when he began to describe the race as a referendum on the president's policies.

Rounds served as governor from 2003 to 2011. His Senate campaign earned endorsements from the Tea Party to 2012 Republican presidential nominee Mitt Romney.

While governor, Rounds signed legislation to put an abortion ban on the ballot; it was defeated. He promised to slow the president's initiatives in Washington.

West Virginia

Shelley Moore Capito, Republican

A six-term veteran of the U.S. House, Capito, 60, is the first woman ever elected to the U.S. Senate from West Virginia and the first Republican senator from the state in more than 50 years.

She comes from a long line of politicians: Her father represented the state in Congress and was elected governor three times.

Capito, who disagrees with the Tea Party on cuts to federal programs and on social issues, has said that Roe vs. Wade should not be overturned. However, she has voted to ban abortions after 20 weeks.

She opposes Obama administration efforts to curtail coal-fired plants.

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