WASHINGTON (AP) — The conservative tea party movement scored a win over the Republican establishment as its favorite captured the Republican nomination for U.S. Senate in Nebraska in a bitter race that highlighted the fissures within the party.

Voters in Nebraska and West Virginia were deciding their party's lineups Tuesday in the latest round of primaries ahead of the November elections, which will determine control of Congress for the last two years of President Barack Obama's second term.

Republicans aim to increase their majority in the House of Representatives and are cautiously optimistic about gaining a majority in the Senate, where Democrats now control 55 of 100 seats. That would give Republicans full control of Congress for the first time since they were swept out in 2006, during President George W. Bush's final term. Obama has already seen much of his legislative agenda stymied since Democrats lost control of the House of Representatives in 2010.

In Nebraska, university president Ben Sasse captured the Republican Senate nomination with 48 percent of the vote in a five-man primary.

The limited government, anti-tax tea party movement, which was blamed by establishment Republicans for the party's recent failures to take the Senate, has struggled this year as candidates have lost to establishment favorites in Texas, North Carolina and Ohio.

Nebraska represented the insurgent movement's best remaining shot to secure a Senate nomination. Tougher tests for the tea party will come in next Tuesday's primaries in Georgia, Idaho and especially Kentucky, where Matt Bevin faces an uphill battle for the nomination against Senate Minority Leader Mitch McConnell, the epitome of the Washington establishment.

For months, Sasse was locked in a negative race with former State Treasurer Shane Osborn, who had the support of McConnell and his allies. Sasse had the backing of some tea party and pro-business groups as well as two of the right's heroes — ex-Republican vice presidential candidate Sarah Palin and Sen. Ted Cruz of Texas. Osborn sank to third in the primary.

Sasse focused on his conservative credentials, opposition to abortion, support for gun rights and the goal of repealing and replacing Obama's health care law, which is despised by conservative activists who influence the primary process. He is a heavy favorite against Democratic nominee Dave Domina in the Republican-leaning state.

Republicans need to gain six seats to grab a Senate majority, and are hopeful of picking up these seats from Democrats in states that supported Republican Mitt Romney in the 2012 presidential election.

Republicans had also hoped to capture the Senate in 2010 and 2012, but saw their chances fade as conservative tea party candidates ousted establishment favorites in primaries but were considered too extreme in the general election and lost to otherwise vulnerable Democrats.

In West Virginia, two women, Republican Rep. Shelley Moore Capito and Democrat Natalie Tennant, cruised to primary wins. They will square off in a showdown that will give the state its first female U.S. senator.

Capito, a seven-term congresswoman and daughter of a former governor, is the heavy favorite in a socially conservative state that has become increasingly Republican. If she wins, she would be the first Republican senator from West Virginia since 1959.