"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 statement released by Brannon's campaign.

"The American people don't want more politicians in the U.S. Senate who will continue to expand the size of government. We need Greg in the Senate to provide vital reinforcements to help reverse out-of-control spending, restore constitutional limitations on our federal government, and fight back against President Obama's agenda."

Brannon is running against North Carolina House Speaker Thom Tillis (R), the favorite of national strategists and establishment Republicans in the state, and Rev. Mark Harris (R). The endorsement from Paul, a hero to Tea Party and libertarian Republicans, could help him raise his profile and help his fundraising.

The winner of the Republican primary will face Sen. Kay HaganKay Ruthven Hagan2020 Dems compete for top campaign operatives Senate GOP rejects Trump’s call to go big on gun legislation Politics is purple in North Carolina MORE (D-N.C.) in the general election. Hagan is a top GOP target — national Republicans believe her seat could be the one that determines Senate control. A more competitive GOP primary could boost her chances for reelection.