(CNN) Senator Lindsey Graham is ending his presidential campaign, he told CNN during an exclusive interview airing Monday. 
 
 "I'm going to suspend my campaign. I'm not going to suspend my desire to help the country," the South Carolina senator said in a wide-ranging and candid discussion in which he acknowledged: "I've hit a wall here." 
 
 He made the official announcement in an email to supporters and Youtube video posted Monday morning. 
 
 Graham is known for his quick wit and famous for his one-liners (just ask Princess Buttercup about his retort from the last debate), but he was sober, serious and emotional as he described his decision to leave the race just weeks before the voting begins. 
 
 One thing is clear: Graham still wants his voice heard on the direction his party is headed, especially with regard to the Middle East. 
 
 "Here's what I predict. I think the nominee of our party is going to adopt my plan when it comes time to articulate how to destroy ISIL," he said. "We've fallen short here, but the fight continues. To those who are doing the fighting, I want to be your voice. To those in the Republican Party who want to win, check my plan out. Hillary, if you get to be President, I'll help you where I can. I hope you're not. But if you are, I'll be there to help you win a war we can't afford to lose." 
 
 Graham's decision -- which leaves a field of 12 main GOP candidates (CNN had 13 at its last Republican debate, including Graham) -- comes just days after the CNN Republican Presidential Debate in Las Vegas, where he was widely viewed as dominating the undercard debate. 
 
 "Four months ago at the very first debate, I said that any candidate who did not understand that we need more troops on the ground in Iraq and Syria to defeat ISIL was not ready to be Commander in Chief," Graham wrote in the email. "At the time, no one stepped forward to join me. Today, most of my fellow candidates have come to recognize this is what's needed to secure our homeland." 
 
 He added, "While we have run a campaign that has made a real difference, I have concluded this is not my time." 
 
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 "My biggest problem is a lot of people like what I say, but not a lot of people hear it," he told CNN. "I don't want to be the undercard voice. I cannot tell you how frustrating it has been to have spent all this time and effort preparing myself to be Commander-in-Chief and to be put at the 'kiddie table'." His advice to his party as it relates to the debate format: "Never do this again." 
 
 Graham's campaign strategy had been laser-focused on New Hampshire: Place high in that first primary state on February 9 and use the momentum to propel him forward. So why not hold out until then? 
 
 Photos: Lindsey Graham's political career Photos: Lindsey Graham's political career Click through to see highlights from U.S. Sen. Lindsey Graham's political career: Hide Caption 1 of 14 Photos: Lindsey Graham's political career Graham; Sir Elton John, center; and filmmaker and John's husband, David Furnish, pose after testimony at a U.S. Senate hearing on the global fight against AIDS on May 6, 2015. Graham and Democratic Sen. Patrick J. Leahy of Vermont hosted John as part of their bipartisan effort to combat HIV infection. Hide Caption 2 of 14 Photos: Lindsey Graham's political career Graham rushes to the Senate chamber to vote on an attempt to override U.S. President Barack Obama's veto of the Keystone XL Pipeline legislation March 4, 2015. Graham was elected to the U.S. Senate in 2002 and was re-elected in 2008 and 2014. Hide Caption 3 of 14 Photos: Lindsey Graham's political career Graham listens to testimony during a Senate Armed Services Committee meeting on national security strategy on January 27, 2015. According to his website , Graham continues to serve his country in the U.S. Air Force Reserves as a senior individual mobilization augmentee to the judge advocate general. Hide Caption 4 of 14 Photos: Lindsey Graham's political career Graham arrives for a closed briefing of the Armed Services Committee on July 30, 2014. Before serving in the Senate, Graham was elected to the U.S. House of Representatives in 1994. Hide Caption 5 of 14 Photos: Lindsey Graham's political career Graham talks to U.S. Sen. Marco Rubio, R-Florida, before a news conference on Capitol Hill on July 24, 2014. Hide Caption 6 of 14 Photos: Lindsey Graham's political career Graham and U.S. Sen. Ted Cruz, R-Texas, right, listen as President Barack Obama delivers the State of the Union address on January 28, 2014. Graham was in the U.S. Air Force and logged six-and-a-half years of service on active duty as an Air Force lawyer. Hide Caption 7 of 14 Photos: Lindsey Graham's political career Graham holds a news conference on Benghazi, Libya, at the U.S. Capitol on October 30, 2013. From left, he is flanked by Sen. John McCain, R-Arizona; Rep. Jason Chaffetz, R-Utah; and Rep. Jim Jordan, R-Ohio. Graham has been an outspoken critic of how the Obama administration has handled the September 11, 2012, attack on the U.S. diplomatic, in which four U.S. citizens died. Hide Caption 8 of 14 Photos: Lindsey Graham's political career Israeli Prime Minister Benjamin Netanyahu, center, meets with U.S. Sen. John McCain, R-Arizona, and Graham on June 30, 2013, in Jerusalem. Hide Caption 9 of 14 Photos: Lindsey Graham's political career McCain, left, and Graham speak during a news conference about Benghazi on February 14, 2013, on Capitol Hill. Hide Caption 10 of 14 Photos: Lindsey Graham's political career Graham talks with reporters before heading into the Senate Republican Caucus policy luncheon at the U.S. Capitol May 8, 2012. Hide Caption 11 of 14 Photos: Lindsey Graham's political career Graham speaks to reporters after a news conference about his Social Security reform plan at the U.S. Capitol on April 13, 2011. Hide Caption 12 of 14 Photos: Lindsey Graham's political career Graham, left, and McCain call on participants during a health care town hall meeting on September 14, 2009 at the Citadel in Charleston, South Carolina. According to his website, Graham is a native South Carolinian and grew up in a blue collar family in the small town of Central, where his parents ran a restaurant and pool hall. Hide Caption 13 of 14 Photos: Lindsey Graham's political career U.S. President George W. Bush, left, stands with Graham on the steps of Air Force One at the airport in Greenville, South Carolina, in March 2002. Hide Caption 14 of 14 
 
 "I'm not trying to hold out. I'm trying to make a difference. I think the best way for me to make a difference is to think about helping somebody else," he said. 
 
 In another key primary state, South Carolina, he faces a Monday December 21 deadline to keep his name off the ballot, potentially helping Graham avoid an embarrassing showing in his home state. Asked whether that fueled his decision to drop out now, Graham said no and added that he'd risk it if he saw a way to turn things around. 
 
 "At the end of the day, I'm not going to be competitive in my state," he said. "I'm not going to be competitive outside my state." 
 
 Asked who he would endorse, Graham demurred. "I'm going to take some time with my family. Going to think about what I should do. I have no intention of endorsing anyone right now." Later, he said that if he were to endorse, he's looking for the candidate best fit to be Commander-in-Chief and also who can win. 
 
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 As for the candidate Graham has traded barbs with the most since he entered the race in early June, Graham struck a markedly softer tone toward Donald Trump."You're doing really well. I'm impressed with your campaign," he said. 
 
 Graham -- who recently urged Republicans to tell Trump to " go to hell " -- also did not rule out accepting a Cabinet position in a Trump administration in the future. 
 
 But he did offer these parting words for Trump: "We're at war. A lot of men and women are at risk overseas. Watch what you say over here." 
 
 "You may wind up being the nominee of the Republican Party," he added. "The Republican Party's future may be in your hands. The future of the country will be in your hands if you're President of the United States. This is not a game show. This is not a reality show." 
 
 Candidly, Graham said he has a lot of regrets looking back at his campaign. "I regret that I haven't been a better candidate. I regret that I never got on the big stage. I regret that I didn't make it to the final group. But that's just about me. I have no regrets about running for President," he said. "It has been the joy of my life to run for President of the United States." ||||| poster="http://v.politico.com/images/1155968404/201512/1742/1155968404_4670117257001_4670065622001-vs.jpg?pubId=1155968404" true Lindsey Graham drops out of presidential race The senator's exit puts up for grabs the support of a number of important South Carolina donors and operatives. 
 
 South Carolina Sen. Lindsey Graham on Monday bowed out of the presidential race after failing to attract any significant support, despite his memorable zingers and passionate commitment to pushing a hawkish foreign policy agenda. 
 
 His announcement came on the same day as the deadline hit for him to remove his name from the South Carolina primary ballot, a date that had been closely watched amid speculation that Graham would want to avoid a potentially poor performance in his own state’s contest. 
 
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 “I was hoping not to have to make this call, but I think the time has come for me to suspend my campaign,” he said as he opened a call with supporters on Monday morning. 
 
 Graham, a well-respected voice in the Senate who easily won reelection in 2014 despite several attempts to unseat him by primary challengers, has nonetheless failed to gain traction in the presidential contest. The senator, who entered the race in part because he hoped to push foreign policy issues to the forefront on the debate stage, has repeatedly been relegated to undercard contests, where he has earned positive reviews but hardly any boost in poll numbers. 
 
 Even with Graham dropping out, the GOP field still has 13 contenders, with a little more than a month before the Iowa caucuses. 
 
 “We’ve come to a point now where I just don’t see how we grow the campaign without getting on the main stage,” he said. “One of the biggest problems we’ve had was to get our voice on equal footing with others. This second-tier debate process has been difficult for us. I think we’ve done well in the debates, it’s just hard to break through because the buzz doesn’t last very long.” 
 
 Graham's latest RealClearPolitics national polling average is only .5 percent. In New Hampshire, the state in which Graham has made the biggest efforts, campaigning there as recently as this weekend with ally John McCain, Graham’s average is 0 percent. Graham’s exiting of the race comes just weeks before the next Republican presidential debate comes to his home state, on Jan. 14. 
 
 By leaving now, he frees up some South Carolina donors and operatives, who had either been backing Graham or staying neutral out of respect for the state’s senior senator. 
 
 “I’ll watch and see where Lindsey goes,” said Katon Dawson, the former South Carolina GOP chairman who previously supported Rick Perry, who has also left the race. “After Perry got out, in deference to Sen. Graham, I’ve been waiting to see if he stays or leaves. Now I’ll be real interested in seeing what Lindsey’s opinions are on all of them after having campaigned with them.” 
 
 He added that in particular, House and Senate members and local officials will now feel more free to align with another candidate. 
 
 Graham also positions himself as a kingmaker in the Feb. 20 South Carolina primary. It’s unclear whom Graham might back, but he has made his disdain known for two of the other candidates currently leading in South Carolina: Donald Trump and Ted Cruz. 
 
 “Sen. Graham has an incredibly strong and loyal grassroots network that will be wooed by many campaigns,” said Matt Moore, the current South Carolina GOP chair. Much of the top talent in the Republican operative class in the state comes from Graham’s world. “I think his network and Sen. Graham’s endorsement will have an impact on the race,” should he choose to make one. 
 
 Graham told CNN in an interview that he doesn't have any imminent plans to endorse. "I'm going to take some time with my family. Going to think about what I should do. I have no intention of endorsing anyone right now," he said. 
 
 Graham, with his signature quick wit, made a brand out of his one-liners, particularly those aimed at Trump, and also stood out in the race for his particularly hawkish foreign policy stance. He has advocated for sending 20,000 troops to fight the Islamic State, one of the most aggressive — and specific — proposals from the presidential candidates, many of whom have been quick to cite areas of agreement with Graham. 
 
 The South Carolina senator received warm words after his announcement on Monday, from both Republicans and Democrats. "Nobody is more clear-eyed about ISIS than my friend @GrahamBlog. As he leaves the race I hope our party & country listen to his counsel," Jeb Bush tweeted. 
 
 John Kasich also took to Twitter to say, "Enjoyed Sen. @LindseyGrahamSC's wit & respect his seriousness on nat’l security—experience matters. Best wishes to him. -John." 
 
 David Axelrod, a former campaign strategist to President Barack Obama, expressed regret that Graham was stuck on the undercard stage, tweeting, "I disagree with @GrahamBlog on many things, but I deeply respect him. He lit up the undercard debates. Too bad he never made the main stage!" 
 
 McCain, meanwhile, issued a statement saying it was a "pity" that the debate set-up muted Graham's message. "With Senator Lindsey Graham's announcement, Republicans lost our most qualified, thoughtful, fearless and honest presidential candidate, not to mention the candidate with the best (and it seemed sometimes the only) sense of humor," he said in a statement. 
 
 Graham, during his call to supporters, said he was proud of the presidential campaign he ran. “I never went down the demagoguery trail,” he said Monday morning, in a shot at Trump. “I didn’t get into this campaign to run other people down, and to bring out the worst in who we are as a party or a country. I think what makes America great is our tolerance for each other and the fact that we respect people who are different. That’s so different than our enemies.” 
 
 He went on to add, “I tried to be a voice for those fighting this war.” 
 
 Alex Isenstadt contributed to this report.
– One of the mainstays of the undercard GOP debates is out: Lindsey Graham tells CNN that he's suspending his campaign for president. "I've hit a wall here," says the conservative South Carolina senator. Graham has been consistently polling near the bottom of the pack and hasn't qualified for the main debate once. The likely key factor: Monday was the deadline for Graham to remove his name from the primary ballot in South Carolina, notes Politico. Being able to do so allows him to avoid the possibility of an embarrassing home-state loss. "Here's what I predict. I think the nominee of our party is going to adopt my plan when it comes time to articulate how to destroy ISIL," says Graham. "To those in the Republican Party who want to win, check my plan out. Hillary, if you get to be president, I'll help you where I can. I hope you're not. But if you are, I'll be there to help you win a war we can't afford to lose." An email to supporters was expected to go out later Monday.