South Carolina Sen. Lindsey Graham said Sunday that winning the 2016 presidential election should take a back seat to stopping Donald Trump from destroying the Republican Party by becoming its presidential nominee.

"We can lose an election, but I don't want us to lose our heart and soul," Graham said Sunday on CBS' "Face the Nation." "If we nominate Donald Trump, and he carries the banner of the Republican Party, given who he is and what he said about immigrants, about Muslims and young women, we will not just lose the election. We have lost the heart and soul of the conservative movement. That's what is at stake."

Graham, who made little headway in his own presidential bid last year, is working to help Sen. Ted Cruz capture the Republican nomination. The South Carolinian differs with Cruz on many issues, but argues Texas Republican is worth supporting to stop Trump.

"Donald Trump would be an absolute disaster for the Republican party, destroy conservatism as we know it," Graham said. "We would get wiped out."

"Mr. Trump is an interloper and ... a demagogue of the greatest proportion," Graham said.

Graham said it would take the GOP "generations to overcome a Trump candidacy."

Trump's "foreign policy is gibberish" Graham said, arguing Trump would be unable to tackle "a mess" in the Middle East.

But "Mideast politics to me seem to be less of mess right now than Republican Party," Graham added. "And that is saying a hell of a lot."

Graham said Ohio Gov. John Kasich should drop out of the presidential race or strategically cooperate with Cruz.

"John, if I thought you could win, I would be behind you, because you are the most electable candidate," Graham said. "Work with Ted to deny Trump 1,237 or 1,239, or whatever the number is."

Kasich is campaigning in Utah, an approach Graham and other Republicans complain could cost Cruz a chance to top a 50 percent threshold for winning all the state's delegates, thus denying Trump any gain from the state.

Kasich who also appeared on "Face the Nation" Sunday, reacted with irritation to suggestions he should drop out.

He argued Cruz cannot win the nomination before the convention and that Trump will also fail to do so.

"Why don't they drop out?" Kasich said.