CONCORD, N.H. — Gov. Chris Christie had nothing but nice things to say about rival Rand Paul's departure Wednesday from the race for the Republican presidential nomination, signaling a shift in tone from his other public comments about the U.S. senator from Kentucky.

Christie, who has often traded barbs with Paul over the years, complimented the senator for running a substantive campaign.

The governor — one of nine Republicans still running for president — said he would even help Paul's 2016 Senate re-election campaign if asked.

"I have great respect for Senator Paul," he said at a presidential endorsement event in Concord.

"He stands for a certain point of view in our party, regarding national security issues, and I respect his point of view. I disagree with it, but I respect it," Christie said. "I think Senator Paul, through most of this campaign, conducted himself like a gentleman."

Christie lauded Paul for advocating his policy positions in a "thoughtful way," not, Christie said, by "sloganeering and all the rest like some other folks do."

He added: "(Paul) is willing to answer the questions and stand out in front of a group."

And if Paul needs any help getting re-elected to the Senate this year, Christie is willing to help.

"I wish him the best of luck with his re-election," he said. "If he needs me to come down there and campaign for him, I'd be happy to do that because he's a good guy to have in the United States Senate."

Paul and Christie have a history of clashes.

In 2013, Christie accused Paul of using his name and identity within the Republican Party "to get attention in the national media."

Paul took some serious swipes at Christie over the governor's remarks against the National Rifle Association as well as the way Christie championed the $50.7 billion Hurricane Sandy aid package.

More recently, the pair attacked one another during the presidential campaign, including a fiery exchange during the first Republican debate in August.

Paul also jabbed the governor over the Bridgegate controversy during the fifth GOP debate in December. That hit came when Paul criticized Christie for advocating shooting down Russian planes, which, he argued, could start a new world war.

Matt Arco may be reached at marco@njadvancemedia.com. Follow him on Twitter @MatthewArco or on Facebook. Follow NJ.com Politics on Facebook.