It seems very unclear how current US actions in Syria achieve either of these aims, though. The status quo in Syria is that Assad holds a significant military advantage and is very slowly regaining ground. The opposition has no serious chance of reversing this position, unless the US sent in active forces. The current US shipment of weapons to the opposition is simply drawing out the war, rather than changing the outcome, and the longer the war goes on, the more people die. Assad is evil. He will kill thousands, if not tens of thousands of people, when (and I say when, not if) he wins. However, that's still less than what the continuation of this war causes, since Assad is still going to win and still going to kill those people, and you have all those extra deaths in the meantime from the process of warring.
Additionally, there is absolutely no guarantee that, even if opposition groups given military support by us managed to overthrow Assad, they would be culturally allied to our interests. The US has a long history of 'the enemy of my enemy is my friend' reasoning that almost never worked. Did the mujahideen bring about an America-friendly government after the Soviet-Afghan War? No. Instead, it brought to power a group which had strong reason to be isolationist, hostile towards major powers, and deeply ethnonationalist thanks to an ingrained revanchism.
The US is not going to beat Assad by continuing present actions. If you want to seriously alter the political outcome in Syria, then the US needs to invade, commit ground troops for policing for a long period of time, and spend enormous amounts of money on a reconstruction programme. This would be significantly more expensive and time-consuming and American-life-endangering than Iraq, where the US did not commit sufficient troops to safeguard the rebuilding process and spent a tuppence on rebuilding the Iraqi state. If you can't commit to that, then you need to accept that US involvement is doing more harm than good, and the best possible thing the US can do is facilitate the immediate end of the war.