Assad says he gave up chemical weapons, but the rebels never had them. Assad's forces have used them before.
Do you mean Assad used them in 2013? I did a little googling when you mentioned this several years ago and I just couldn't come up with anything, but I really don't know* [edited] if they used or were accused of using chemical weapons before the civil war. I mean I don't know of any credible reports that Syria has used chemical weapons before 2013.
Going back to 2013, the Turkish police caught jihadis with sarin. There have been other reports that the rebels have chemical weapons, such as chlorine gas taken from Syrian stockpiles lost during the war, although of course these were very small amounts compared to what the Syrian Army had. However, who is now more credible about having or not having chemical weapons and I think Syria is more credible about having given them up; also, the rebels never admitted having them.
ISIS accused of using chemical weapons recently in Mosul.Syria has faced international condemnation for using chemical weapons. But Islamic State has them too
Well, again, if I knew for sure that the chemical weapons were launched from site X, and something could be done about it, I would.
I know this sounds horribly cynical, but considering the obvious implications that what you're saying is US military involvement in Syria, right?, why would you advocate that? Is there any reason to think the outcome would be different than Viet Nam, Iraq, Afghanistan, or Libya? The amount of casualties in the Syrian war by chemical weapons is very small compared to the 400,000 plus dead, right? Why does this deserve a Tomahawk strike that predictably leads to the Russians backing out of the air force agreement?
Again, it sounds like the first Iraq war: Saddam is a bad guy because he gassed the Kurds. Yes, that's true, but why wasn't he a bad guy when he was gassing the Iranians much more, and with CIA logistical support? And from whence did those chemical and biological weapons come? He got some of them from NATO countries.
My point is that the Aug. 2013 Ghouta chemical weapons attack and the one a couple of weeks ago are not significant militarily or in comparison to overall numbers of casualties. I consider them isolated events, significant for propaganda and as pretexts for further US/NATO involvement. Aside from the moral outrage over chemical attacks, which always provide videos of injured children blamed on "the psychopath Assad" (I'm trying to recall viral videos of injured children by the rebels/terrorists, but nope, somehow not as prevalent), why are they more significant than other casualties, yet somehow less significant than the depleted uranium attacks by the USA in Fallujah? I'm not bringing up Fallujah to sidetrack or pull a tu quoque. I do so because I think it's a valid comparison, admittedly more controversial than sarin.
EDITED for clarity.