Brannon lands Paul endorsement

"Americans are looking for leaders who will honor their oath of office by fighting to ‘protect and defend’ the Constitution, and Greg is the clear choice for conservatives in North Carolina," Paul said in a news release from the Brannon campaign.

In addition to Brannon, House Speaker Thom Tillis and the Rev. Mark Harris, president of the Baptist State Convention, are planning on running. Tillis, a former IBM executive and management consultant, is thought to appeal to business leaders. Harris, a preacher, is thought to be an attractive candidate for "values voters." 

Brannon, an ob-gyn with his own practice in Cary, has drawn support from the tea party, portraying himself as a hard-line, small-government fiscal conservative. Paul's endorsement will burnish that image. 

"As Ted Cruz, Mike Lee and I showed clearly in our campaigns, when you run on principle and excite the grass-roots Republicans and Independents and even Democrats hungry for a change, you win. That's why I support Greg Brannon and expect him to be North Carolina's next Senator," Paul wrote.

The winner of next spring's Republican primary will take on U.S. Sen. Kay Hagan, a Democrat, in the fall general election.