In supporting calls for action against Syria, the 22-member Arab League, which is dominated by Gulf powerhouses Saudi Arabia and Qatar, provides indirect Arab cover for any potential military attack by Western powers.
At an emergency meeting, the Arab League also urged members of the Security Council to overcome their differences and agree on "deterrent" measures.
"The council holds the Syrian regime totally responsible for this heinous crime and calls for all involved in the despicable crime to be given a fair international trial like other war criminals," the Arab League said in a statement.
Heyman predicted a possible three-phase campaign, with the first step — the encirclement of Syria by Western military assets by air and sea — already underway.
"Phase two would be a punitive strike, taking out high-value command and control targets and communications centers," Heyman said. "That could be done easily with cruise missiles from ships and aircraft. Phase three would be a massive takedown of Syrian air defenses. That would have to be done before you could take out artillery and armor, which is the key to long-term success."