Motive and Opportunity

The idea that Assad wouldn't have used chemical weapons because he is winning the war is wrong on the assumption.

I've read some say there is no way Assad could be responsible for the latest chemical attack because it would be suicidal to do so when he is winning the civil war.

One, after Trump has said he would stay out of Syria's long conflict the theory holds that rebels did this to blame Assad, knowing Trump would retaliate enough to restore the rebellion's fortunes?

But more basically, Assad has not won the war. After 4-1/2 years of trying, Assad finally took Aleppo at the end of 2016. We'll see if he can hold it.

Even with Aleppo held, Assad has not gained control of much of the western portion of Syria, let alone the east. And the casualties Assad and his allies have endured thus far is astounding. The war is far from won for Assad.

So a Syrian government chemical strike has high value in showing rebels that they are all alone in the world to face Assad who can do whatever he wants without being challenged. Under Obama, Assad launched a big chemical strike in 2013 that did not trigger a "red line" retaliation; and Assad carried out small chlorine gas attacks without triggering an Obama administration retaliation.

Assad had high motivation to show Trump would look away, too; and Assad had reason to believe a small chemical attack would be too little to trigger an American response but enough to crush rebel hopes.

Heck, Assad might have believed the Russian military presence was enough of a shield against American action.

That is why Assad would use chemical weapons, and is a much simpler explanation than any false flag or Russia-Putin conspiracy theory (coughlawrenceodonnellcough).

UPDATE: Oh, and the idea that it couldn't be Sarin--and so is a rebel ruse--because first responders survived rushing to aid victims is potentially refuted by noting that Sarin is a nonpersistent agent that dissipates rapidly.

Militarily it is useful for an attacker who expects their own troops to move into the area soon to exploit the chemical strike.

Or that quality might be useful to deny clear evidence of the compound if enough time passes before the area can be sampled.

Strikes on enemy airfields or deeper rear areas might use persistent agents to deny the enemy the use of that terrain for a longer period of time.

UPDATE: One more related point.

I think it is kind of cute when I hear people blaming Russia for Syria still having--and using--chemical weapons in the civil war! Apparently, Russia is supposed to enforce Syrian compliance.

How adorable to think that! The purpose of the 2013 Kerry-Lavrov chemical weapons deal was never about eliminating Assad's ability to launch chemical strikes.

For Assad, the deal was about preventing President Obama from launching air strikes for violating the "red line" and moving America from foe to ally against ISIL.

For America, it was about freeing Obama from the humiliation of backing down from his "red line" threat about chemical weapons use that he had no interest in enforcing after Assad used chemical weapons.

And Russia just wanted to show they are in the game in the Middle East, to expand their position there.

The people of Syria just got to endure more death, destruction, and flight from the Assad killing machine.

UPDATE: The argument that it doesn't make sense for Assad to use chemical weapons "when he is winning" is an old one. I questioned the assumption of that logic back in 2013, too.