The Kurds were more pro Iranian then not, considering their history going back to 1958, The Shah didn't treat them greatly in '75 but on balance, they didn't persecute them to the same extent,
Yes, WMD got a pass, for two years after Halabja, then many of the same figures who support action against Assad now, Kerry, Biden, Pelosi, were opposed back then,
The question is which circumstance is more likely to bring about an WMD release in a major US city,
I would posit an incursion in favor of a predominantly Islamist faction, btw, has Baghdadi's death, been confirmed like the last two times.
What is more likely, specially considering Rouhani has been fooling Obama with crib notes, re the nuclear program, if Islamists seize portions of Assad's arsenals?