Graham: GOP will get 'slaughtered' if Trump nominee
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Sen. Lindsey GrahamLindsey Olin GrahamTrump says he'll '100 percent' veto measure blocking emergency declaration Overnight Defense: Dems tee up Tuesday vote against Trump's emergency declaration | GOP expects few defections | Trump doubles number of troops staying in Syria to 400 On The Money: Dems set Tuesday vote on Trump's emergency declaration | Most Republicans expected to back Trump | Senate plots to avoid fall shutdown drama | Powell heading before Congress MORE (R-S.C.) argued Wednesday that if Donald TrumpDonald John TrumpAverage tax refunds down double-digits, IRS data shows White House warns Maduro as Venezuela orders partial closure of border with Colombia Trump administration directs 1,000 more troops to Mexican border MORE is the GOP nominee, Republicans will get "slaughtered" in the November election. 

Lambasting the outspoken Republican front-runner as an "opportunist," Graham argued that Trump would kneecap Republicans' hopes of winning back the White House. 
 
"I think he's a kook. I think he's crazy. I think he's unfit for office," Graham, a backer of Trump rival Jeb Bush, said on Fox News's "America's Newsroom."
 
"I'm a Republican. and he's not. He's not a conservative Republican, he's an opportunist," Graham said on the program. "He's not fit to be president of the United States."
Trump pushed back against the broadside, sending several tweets arguing that Graham had no support before ending his own White House bid in December and "no cred" to make the claims.
 
"I will beat Hillary easily," Trump insisted in one of his tweets before going after Fox News for airing remarks from one of his critics on the program.