Sen. Lindsey GrahamLindsey GrahamGun-control supporters plan next steps versus NRA Bipartisan gun measure survives test vote Senate Republicans may defy NRA on guns MORE (S.C.) is dropping out of the GOP race for the White House.
Graham announced his plans in a video message on Monday morning.
"Today, I am suspending my campaign for president," he said.
"I want to thank everyone who has taken this journey with me. You have honored me with your support," Graham added.
CNN first broke the news after Graham told the network of his plans in an interview.
The defense hawk has barely registered in polls and never graduated to the main stage in GOP debates.
Graham had hoped his experience on national security — he is an ally of Sen. John McCain (R-Ariz.) and a member of the Armed Services Committee — might give some life to his campaign.
But he never gained traction in the crowded field. As of Monday, he was averaging 0.5 percent in the RealClearPolitics average of national polls and never scored higher than 2 percent in any major national poll throughout his campaign.
Even in his home state of South Carolina, where he had briefly led earlier this year, Graham has fallen down into the low single digits.
"I got into this race to put forward a plan to win a war we cannot afford to lose and turn back the tide of isolationism that was rising in our party," he said in the video.
"I believe we have made enormous progress."
McCain, the party's 2008 nominee, lamented the loss of the party's "most qualified, thoughtful, fearless and honest presidential candidate.
In a statement, he also panned the "bifurcated debate structure [that] kept [Graham's] voice and views from the wider public that needed to hear them."
The Arizona senator had been Graham's only major endorsement, and it's possible that he'd now hitch his wagon to another candidate.
Graham's decision leaves 13 candidates left in the crowded field. Graham is the fourth GOP candidate to drop out, after former Gov. Rick Perry (Texas), Gov. Scott Walker (Wis.), and Gov. Bobby Jindal (La.).