Rob Maness, one of the five Republicans running for Louisiana’s open Senate seat, said Thursday he has received the endorsement of Kentucky Sen. Rand Paul.

Paul supported Maness, who is running as a political outsider against three sitting Republican lawmakers: Rep. Charles Boustany, Rep. John Fleming and state Treasurer John Kennedy.

“The United States Senate is in desperate need of principled constitutional conservatives committed to protecting individual liberty and that is exactly why I am thrilled to endorse Col. Rob Maness for Senate in Louisiana,” Paul said in a statement.

Paul is the first sitting senator to endorse in the wide-open race to replace Sen. David Vitter, who, after a bruising loss in last year’s governor’s race, will leave the Senate at the end of his term.

Louisiana voters will head to the polls on Nov. 8 in the state’s “jungle primary.” If neither of the nine candidates – including four Democrats – gets more than half of the vote, there will be a runoff a month later.

Back home in Kentucky, Paul has a re-election fight of his own. His opponent, Lexington Mayor Jim Gray, has made the case that Paul is overly ambitious to represent the Bluegrass State in the Senate, and in a tweet on Thursday, accused Paul’s endorsement spree of being about higher ambitions, yet again.