Sen. Lindsey Graham on Monday suspended his campaign for president.
The South Carolina Republican took credit for quashing anti-war sentiment within the GOP in a video posted on his campaign website.
"I got into this race to put forward a plan to win a war we cannot afford to lose, and to turn back the tide of isolationism that was rising in our party," Graham said. "I believe we've made enormous progress in this effort."
In an exclusive interview with CNN, Graham said, "I've hit a wall here."
Graham thanked his supporters, saying his has been "a problem solvers' campaign."
Graham's withdrawal comes on the final day he can have his name removed from the ballot in his home state of South Carolina. The RealClear politics average of polls conducted in the state shows Graham registering a paltry 1.7 percent support, far behind current front-runner Donald Trump, who is at 33.7 percent.
Graham's polling numbers rarely reached above 2 percent in the crowded Republican field. This kept him from appearing on the main stage at any of the Republican debates.
University of Virginia political commentator Larry Sabato reacted quickly to Graham's decision, writing on Twitter, "Congrats to Lindsey Graham, who's dropping out and thereby showed good sense. Frees up SC pols to shake up the GOP POTUS race."
Graham has been a fixture in South Carolina politics, winning a seat in the state House of Representatives in 1993 before moving on to serve four terms in the U.S. House. He succeeded Strom Thurmond in the Senate in 2003.