Story highlights Sen. Lindsey Graham said a Trump nomination would tear apart the GOP

The South Carolina Republican said Trump as nominee would do lasting damage to the party

Indianapolis (CNN) South Carolina Sen. Lindsey Graham is predicting "another 9/11" if Donald Trump is elected president.

In an interview on CBS' "Face the Nation" Graham said the Republican Party is in the midst of a "civil war" and called Trump's foreign policy positions dangerous.

He pointed to former House Speaker John Boehner's comments about his friendly relationship with Trump, and Boehner's dismissal of Texas Sen. Ted Cruz, Trump's chief Republican presidential rival, as "Lucifer in the flesh."

"There's a civil war going on in the Republican Party, obviously," Graham said. "John and I are very close friends, but he's embracing Donald Trump, and I am not. Why? Because I believe Donald Trump's foreign policy is isolationism. It will lead to another 9/11."

Graham, a one-time GOP primary rival of Trump, continued: "Let me just tell my friends, who I really do respect, if you are embracing Donald Trump, you're destroying conservatism. You will make it hard for this party to ever regain footing with Hispanics, because his immigration proposal is unworkable, is hateful. When it comes to women, we're alienating women, who should be coming our way after eight years of Obama."

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