Answer: The United States could destroy Bashir’s control over his chemical weapons.
ForeignPolicy.com and others report that communications intercepts suggest some confusion over the order to use CW. If you were to make a list of things to worry about, loss of control over the Syrian CW stocks would be at or near the top. One of the good things about Bashir to date has been that he at least controls these weapons.
If the United States feels compelled to attack Sryia, one popularly discussed target set is command and control. Well, that may be the last thing you want to do if you worry about CW getting dispersed among all sorts of bad actors. Even attacking possible CW sites with untried special munitions that could incinerate (hopefully) CW stocks (but risking dispersing agent and munitions in the process) MIGHT be better. Maybe just hitting airfields/aircraft, completely unrelated to CW is a better way of causing Bashir to pay a price.
Related note: If the Administration releases transcripts of communications, be advised that these can be deceptively convincing. Written words can convey meaning not intended when they are spoken…especially when translated. Also, context is lost. For example, in Iraq we thought the Iraqi term for chemical weapons was pretty clear, but it turned out that they used the same term for white phosphorus munitions.