US foreign policy regarding Syria publicly vacillates between seeking to defeat the Islamic State to achieving regime change in Damascus. Even at face value, these two objectives are contradictory, even paradoxical.
Overthrowing the government of Libya in 2011 thrust extremist groups (used by the US to overthrow Tripoli in the first place) into power across the nation, leaving it bitterly divided and in constant conflict since. The collapse of a unified Libya also allowed Al Qaeda and its spin-off, the Islamic State, to flourish unchecked. There is little evidence to suggest that anything else but precisely this scenario would also unfold should the government in Damascus likewise be overthrown.
The conflict in Syria, raging since it was triggered by US-backed armed groups in 2011, has in fact created the very conditions in which the Islamic State rose to prominence, springing forth from designated terrorist organisation, Jabhat Al Nusra, also known as Al Qaeda in Syria. In other words, it was the pursuit of regime change by the US that gave rise to the very extremism it now claims it is involved in Syria, Iraq and now also Libya to defeat.