Top Republican Sen. Lindsey Graham, a vocal critic of Donald Trump throughout the election cycle, slammed the president-elect's views on foreign policy in a wide-ranging interview with Business Insider last week. He called Trump a "fool" when it comes to Russia, said the billionaire businessman has "zero idea" about how to defeat the terrorist group ISIS , called his views on the NATO alliance "dangerous," and said Trump "doesn't know anything" about foreign policy writ large.