Sen. Lindsey Graham, R-S.C., is convinced GOP front-runner Donald Trump's foreign policy platform could lead to another Sept. 11, 2001, terror attack.

Graham is afraid another such catastrophe could loom in the not too distant future if Trump is elected as the next commander in chief. He told "Face the Nation," "I believe Donald Trump's foreign policy is isolationism. It will lead to another 9/11."

Graham Behind Texas Sen. Ted Cruz

Graham, who was once a candidate for the GOP nomination and has since endorsed Texas Sen. Ted Cruz, added a "civil war" is now brewing within the GOP ranks for control of the party.

"There's a civil war going on in the Republican Party," he said. Referring to former House Speaker John Boehner, R-Ohio, who last week called Cruz as "Lucifer in the flesh," Graham added, "John and I are very close friend, but he's embracing Donald Trump, and I am not."

Graham went on to point to the Republican presidential primary in Indiana, on May 3, as a critical time, branding it a "big test" for the anti-Trump movement.

"I'm advising Ted, go to the last vote," he said. "Trump's gotten 40 percent of the popular vote. That doesn't give you 1,237 delegates. I think you can still stop him, even if you lose in Indiana."

In Graham's mind, Trump can't win in November's general election given all the divisive rhetoric he has lobbed throughout primary season, including a vow to deport as many as 11 million immigrants and build a wall along the Mexican border to further keep them out.

"There's been a lot of talk about Lucifer," he said. "I think Lucifer may be the only person Trump could beat in a general election. When it comes to women and Hispanics, Trump polls like Lucifer."

Graham Believes Hillary Clinton Would 'mop Floor' With Trump

While deriding Democratic front-runner Hillary Clinton as a "flawed candidate," Graham added he sees her easily dismantling Trump.

"She will mop the floor with Trump," he said. "With women and Hispanics, they hate Donald Trump because he's so harsh and he's so cruel."

Graham went on to sound the alarm that a vote for Trump is a stand against overall conservatism, warning that the continued rise of Trump will make it hard for the GOP to ever gain solid ground with Hispanics.

"Be your own person," he advised other Republican lawmakers who could find themselves be on the ballot alongside Trump in 2016. "Reject Donald Trump's approach to solving immigration, because it won't work and it's hateful."

Related