"Syria is the single largest repository of this stuff [chemical weapons], so as a consequence you go after the delivery systems, fuel depots, airways, command and control," Miller said. "And then you broaden it out from there to go to artillery units that have lost these things, aircraft that have dropped them."
The U.S. military has weapons other than Tomahawk missiles that could be used to target chemical weapons facilities with the objective of destroying the stockpiles, Mansoor said.
In a July letter to the Senate Committee on Armed Services, Gen. Martin Dempsey said that American military forces were prepared for a number of options, including training the Syrian opposition, establishing a no-fly zone, and conducting strikes "to prevent the use or proliferation of chemical weapons."
"We do this by destroying portions of Syria's massive stockpile, interdicting its movement and delivery, or by seizing and securing program components," Dempsey wrote in July, saying that seizing control of the majority of the regime's chemical weapon supply would involve ground troops. "At a minimum, this option would call for a no-fly zone as well as air and missile strikes involving hundreds of aircraft, ships, submarines, and other enablers."
In the event of a strike of any size, it may take days or longer to determine the effect on Assad's power.
(Read more: Syria looms as traders await jobs report)
"How do you measure the impact we had on the Syrian regime's thinking about the situation? That's tricky, and can only be measured if we see a response and a change in behavior," White said.
At best, a strike could show that the U.S. is serious about the deteriorating situation in Syria, Mansoor said, while at worst it could convince Assad that Obama has played his one hand. After limited, separate cruise missile strikes against al-Qaeda forces in Afghanistan and Iraqi dictator Saddam Hussein in the late 1990s, the targets were only "emboldened," he said, as it seemed the U.S. was not "willing to do something even more."
And while the administration may have narrowed down its strike plans, decisions can be made right up to the time cruise missiles are fired or bombs are dropped, White said.
"I remember a case in a previous administration, I won't get into the details, where the president was presented with targets to strike and he looked at the images and he said, 'What's this over here?' and he was told what it was," White said. "And he said, 'OK, why don't we hit that.'"
—By Matthew DeLuca of NBC News