List with no order of importance:

1. Syria isn't at war with the US or any other Western nation. Never invaded neighbors. Like the other Middle Eastern countries that the US has ruined, it was stable until this unnecessary intervention.

2. It's a huge waste of resources for no gain. The time and materials that went into building what is destroyed as well as the military consumables. The net balance of war is always negative. When fighting or supporting pointless conflicts like this, even more so. It would be less destructive to just give the military-industrial complex their billions for not going to war. At least with the US government, they seem to value destroying other nations more than building their own.

3. It creates more refugees that end up in Western countries.

4. Cultural and historical damage, lost artifacts and art.

5. Lives lost ("collateral damage").

6. It doesn't respect the autonomy and right to self-determination of other nations.

7. Golden rule, how would you feel if the shoe was on the other foot.

8. Fighting for "democracy" is very Western-centric and presumes that our system of governance is more suitable than the existing systems in these countries.