First on CNN: Graham ends his campaign for the White House

Updated 2:14 PM EST, Mon December 21, 2015
Republican presidential candidate Sen. Lindsey Graham is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015.
Ethan Miller/Getty
Republican presidential candidate Sen. Lindsey Graham is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015.
Now playing
01:12
Sen. Lindsey Graham drops out of GOP race
CNN
Now playing
01:21
Lindsey Graham: Donald Trump has 'conned' Republicans
CNN
Now playing
01:36
Lindsey Graham: 2016 election 'a race to the bottom'
(Left to right) U.S. Sen. Lindsey Graham (R-SC), U.S. Sen. John McCain (R-AZ) and U.S. Sen. Ted Cruz (R-TX) listen as U.S. President Barack Obama delivers the State of the Union address to a joint session of Congress in the House Chamber at the U.S. Capitol on January 28, 2014 in Washington, D.C.
Win McNamee/Getty Images
(Left to right) U.S. Sen. Lindsey Graham (R-SC), U.S. Sen. John McCain (R-AZ) and U.S. Sen. Ted Cruz (R-TX) listen as U.S. President Barack Obama delivers the State of the Union address to a joint session of Congress in the House Chamber at the U.S. Capitol on January 28, 2014 in Washington, D.C.
Now playing
01:11
Watch Lindsey Graham go from hating to supporting Ted Cruz
DES MOINES, IA - OCTOBER 31: Republican presidential candidate Sen. Lindsey Graham (R-SC)  speaks at the Growth and Opportunity Party, at the Iowa State Fair October 31, 2015 in Des Moines, Iowa. (Photo by Steve Pope/Getty Images)
Steve Pope/Getty Images North America/Getty Images
DES MOINES, IA - OCTOBER 31: Republican presidential candidate Sen. Lindsey Graham (R-SC) speaks at the Growth and Opportunity Party, at the Iowa State Fair October 31, 2015 in Des Moines, Iowa. (Photo by Steve Pope/Getty Images)
Now playing
02:29
Lindsey Graham: 'Pro-life' platform will be a hard sell
CNN
Now playing
00:49
Ted Cruz 's foreign policy 'as wrong as Obama's'
lindsey graham jeb bush endorsement nr_00000707.jpg
WCIV
lindsey graham jeb bush endorsement nr_00000707.jpg
Now playing
02:26
Lindsey Graham endorses Jeb Bush
lindsey graham suspends presidential campaign_00002120.jpg
lindsey graham suspends presidential campaign_00002120.jpg
Now playing
00:21
U.S. Sen. Lindsey Graham suspends presidential campaign
Now playing
02:25
Sen. Graham: West not showing resolve in ISIS fight
graham unhealthy obama hatred newday_00001316.jpg
CNN
graham unhealthy obama hatred newday_00001316.jpg
Now playing
00:52
Graham calls out GOP's 'unhealthy' dislike of Obama
The PostTape with Lindsey Graham and Kate Bolduan_00020809.jpg
The PostTape with Lindsey Graham and Kate Bolduan_00020809.jpg
Now playing
02:36
Kate Bolduan puts Lindsey Graham in the hot seat
lindsey graham cnn gop debate i miss george w bush sot_00004616.jpg
lindsey graham cnn gop debate i miss george w bush sot_00004616.jpg
Now playing
00:47
Sen. Lindsey Graham: 'I miss George W. Bush'
lindsey graham donald trump xenophobic bigot interview newday_00005811.jpg
lindsey graham donald trump xenophobic bigot interview newday_00005811.jpg
Now playing
03:34
Graham: Trump is a 'race-baiting, xenophobic' bigot (2015)
john mccain lindsey graham paris isis intv newday_00021005.jpg
CNN
john mccain lindsey graham paris isis intv newday_00021005.jpg
Now playing
04:57
John McCain: 'ISIS is not invincible'
senator lindsey graham paris terror attacks tapper intv sotu_00005009.jpg
senator lindsey graham paris terror attacks tapper intv sotu_00005009.jpg
Now playing
01:58
Sen. Graham: The worst is yet to come with ISIS
Lindsey Graham Date Marry Disappear Election 2016 AR ORIGWX_00000000.jpg
Lindsey Graham Date Marry Disappear Election 2016 AR ORIGWX_00000000.jpg
Now playing
01:44
Who would Lindsey Graham date, marry or make disappear?
Senator Lindsey Graham Zingers GOP debate mss orig_00004217.jpg
Senator Lindsey Graham Zingers GOP debate mss orig_00004217.jpg
Now playing
01:07
Lindsey Graham: Master of the zinger?
donald trump car wreck lindsey graham intv tsr_00012018.jpg
IJReview.com
donald trump car wreck lindsey graham intv tsr_00012018.jpg
Now playing
01:40
The stunt video arms race
Surrounded by supporters waving signs and flags, U.S. Sen. Lindsey Graham (R-SC) announces his candidacy for United States President during an outdoor event on June 1, 2015 in Central, South Carolina. Graham is the ninth Republican to join the race for president in 2016.
Photo by Jessica McGowan/Getty Images
Surrounded by supporters waving signs and flags, U.S. Sen. Lindsey Graham (R-SC) announces his candidacy for United States President during an outdoor event on June 1, 2015 in Central, South Carolina. Graham is the ninth Republican to join the race for president in 2016.
Now playing
02:09
Who is Lindsey Graham?

Story highlights

Sen. Lindsey Graham told CNN's Kate Bolduan in an exclusive interview that he is ending his presidential campaign

Graham is an experienced foreign policy voice, but his campaign failed to take off despite strong showings at the GOP undercard debates

Watch CNN’s full exclusive interview with Sen. Lindsey Graham at 11 a.m. ET on “At This Hour”

(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.

However, Graham was never able to break onto the main stage after announcing his candidacy in early June — a reality of the Republican Party’s new debate structure that he blames at least in part for his struggles. Graham limped along at less than one percent in national polls, and, in the most recent CNN/ORC national poll, he barely registered. He failed to even qualify for the undercard round in the Fox Business debate in November.

“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.”

Related: Lindsey Graham’s best lines from the CNN debate

01:35 - Source: CNN
Graham: 'If you want to win this war, follow me'

“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?

“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.

03:34 - Source: CNN
Graham: Trump is a 'race-baiting, xenophobic' bigot (2015)

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.”