By Lisa Mascaro, Tribune Washington Bureau

WASHINGTON — Republican Senator Lamar Alexander of Tennessee won his party’s nomination for re-election Thursday in one of the last of the divisive Tea Party challenges to incumbent senators that have splintered the GOP.

The race had been Alexander’s to lose — positioning a well-known two-term senator and former governor against Tea Party upstart Joe Carr, a state legislator who had big-name support from Sarah Palin and other conservatives but struggled to raise funds.

With five other Republicans running for the nomination, voters split among the choices, which included a doctor, George Flinn, who largely self-financed his campaign. The Associated Press called the race for Alexander about 9:30 p.m. Eastern time.

Earlier in the day, the candidates made a strong push on a sleepy Thursday in August, with Alexander’s volunteers fanning across the state and Carr making last-minute campaign stops, including lunch at the Slick Pig BBQ in Murfreesboro.

Carr had positioned himself as a hard-right alternative to Alexander, who is known as a pragmatic Republican. Once the No. 3 Republican in the Senate, Alexander stepped down from party leadership to focus more recently on ways to bridge the partisan divide with Democrats. Carr used the senator’s vote for a bipartisan immigration overhaul last year as a line of attack because it would have provided many immigrants in the U.S. illegally with a 13-year path to citizenship.

“Any Republican in TN who votes for @SenAlexander is voting for Barack Obama’s amnesty,” tweeted Laura Ingraham, a radio host and Carr supporter, as voters headed to the polls.

The challenger raised $1.3 million compared to Alexander’s nearly $7 million war chest. Carr had little support from the national conservative groups that have pushed other candidates, including Chris McDaniel, the charismatic Tea Party firebrand who is challenging his primary loss to Senator Thad Cochran in Mississippi.

Carr had his own stumbles, including on his debut campaign ad, when he misspelled the word Senate as “Sentate.”

“With Joe Carr, we’re not talking about Rand Paul, we’re not talking about Ted Cruz,” said John Geer, a political science professor at Vanderbilt University.

“The thing people have to keep in mind about Tennessee is, it has a reputation as a red state, and it is, but it’s not as red as you think.”

Photo: Lingjing Bao/Talk Radio News via Flickr