Matthews said if a U.S. military strike in Syria does not stop chemical or nuclear weapon use in the Middle East, another solution will be hard to find.
Matthews said al-Assad's use of chemical weapons broke a global pact even WWII leaders respected.
"I don't like what I'm going to say but it's true," Matthews said. "It's been enforced around the world for decades. We don't use chemical weapons.
"We didn't even use them in WWII," he said. "Hitler didn't even use them. We don't use chemical weapons."