CNN
Sen. Lindsey Graham, one of Donald Trump's most outspoken Republican critics, said in an interview with CNN : " The big mistake Obama made was drawing a red line against Assad. He crossed it, he used chemical weapons, he's still standing. The Russians saw that as weakness and when they intervened, it made Syria much more complicated. You will never end the war in Syria if you leave Assad in power".
The senator had previously criticized US strategy in Iraq and Syria, accusing it of empowering Iran.