Sen. Lindsey Graham (R., S.C.) said President Donald Trump would be making the "biggest mistake of his presidency" if he failed to destroy the Syrian regime's air capabilities in retaliation for Bashar al-Assad's reported chemical attack.
The White House announced Tuesday Trump had canceled a planned trip to Latin America in order to oversee the American response to Syria. Trump condemned Assad as a "monster" and warned of a "big price to pay" after the chemical attack on a rebel-held Damascus suburb, which killed dozens.
Graham told CNN's Kate Bolduan that Trump's recent inclination to pull the U.S. military presence out of Syria would be a mistake on par with President Barack Obama's fateful decision to withdraw American troops from Iraq.
"How many times do we have to learn the same lesson? If you leave too soon, you're going to regret it," Graham said.
Graham said 2,000 troops could do good work in Syria, warning of the consequences of Iran seizing control of the country and its national security implications for the U.S. and Israel.
Bolduan asked Graham what the consequences would be if Trump didn't take military action against Assad in this instance.
"It'd be the biggest mistake of his presidency," Graham said. "Good luck getting North Korea to change their behavior, because you drew a red line ... Trump says he's going to pay a big price. If at the end of the day, he doesn't pay a big price, then President Trump becomes like Obama. Weak in the eyes of our enemies, and unreliable in the eyes of our allies."
Graham called it the "most consequential decision" Trump will make, saying the "big price" Trump warned of needed to be the destruction of Assad's air capabilities.
Graham said Assad should specifically be targeted as a war criminal, adding Trump should signal to North Korea and Iran that he will act if his own "red line" is crossed.
"If this is not an all-out assault on Assad's capability to deliver chemical weapons, if it's not an effort to degrade his regime, it will be a miserable failure," Graham said. "But it's got to be part of a broader strategy."
Graham has been critical of Trump's response a year ago to a Syrian chemical weapons attack, when he ordered a single retaliatory air strike on a Syrian air base.