Sen. Lindsey Graham dropped out of the race for the White House on Monday, leaving 13 Republicans vying for the party's 2016 presidential nomination.
"Today, I'm suspending my campaign for president," the South Carolina senator said in a video posted on YouTube.
Fellow Republican candidate Jeb Bush tweeted his reaction to Graham's announcement. He said he hopes the Republican party and the country will continue to heed Graham's advice.
In his announcement, Graham said he is "far more confident today that [the Republican party] will reject the Obama doctrine of leading from behind and will provide the strong leadership America needs to restore our military."
He said he would continue to work to ensure that the nation takes an active role in fighting its enemies.
"I'm suspending my campaign, but never my commitment to achieving security through strength for the American people," Graham said.
In a November interview with CNBC's "Squawk Box," Graham called for U.S. boots on the ground in the fight against ISIS. Just one month prior, during the CNBC Republican debate, Graham also criticized President Barack Obama's foreign policy.
"Here's the problem. We've being walked all over because the commander in chief is weak in the eyes of our enemies," he said. "Do you think Putin would be in the Ukraine today if Ronald Reagan were president? Why are the Chinese stealing our intellectual property, hacking into our system? Why are they building islands over resource-rich waters? Because they can get away with it. .... Make me commander in chief and this crap stops."
— Reuters contributed to this report