Not quite guys .... but it is indeed a complex delemma .
Firstly, the US does not like Assad, Putin does not like Assad and the Kurds hate Assad. Iran wan't Assad and becasue many Regime commanders would go if Assad left without an acceptable transition process, many Alawites support him.
The US has no intention of removing Assad because they don't want a hot war with either Russia or Iran. Nor does the US wish to be the policeman of the South. That Russia and Iran have elected to take on that task removes pressure from the US IMHO.
Politically, all the US cares about these days is the elimination of ISIS and Al Qaeda. Back in the 80's and early 90's the US did indeed support elements that grew into Al Qaeda and ISIS. The US further facilitated ISIS' growth by not doing enough to stop al Maliki from marginalising and terrorising the Sunni's in Iraq. The one thing the US did do correctly was to (largely) keep the Baghdad regime out of Iraqi Kurdistan. But as I say ... nobody is anybody's true proxy in this region.
The 120 tons of weapons and supplies dropped to the YPG won't be going to ISIS any time soon. During the seige of Korbani last year some of the weapons did fall behind ISIS lines (ISIS later blew the YPG ammo store up) . It is also true that US funded jihaddis handed weapons over to al Nusra in return for safe passage (that is their lives) ..... which is why they are now suporting the YPG more directly. The other reason is that Turkey's attacks on the PKK have also hit the YPG supply chain.
One key issue is the extent to which the Saudi's may be considered proxies of the US. I don't believe they are and other than perhaps some naive minds in Washington nobody else does either. Caught between the Regime/Iran/Russia nexus and the YPG/US/(and probably Russian) alliance the Saudis can't win .... but they can pump weapons accross the line to Arar al Sham and Al Nusra. Turkey does the same but hteir poicies are too incoherent for me to discern ATM.
Pipelines Catgut. We we talking pipelines. Yes the Iraqi Kurds have recently started talking to Iran about pipelines so as not to be deendent on the ones going through Turkey (and recently blown up by the PKK). Yes there is a psuedo war happening in NorthernIraq as I type ... between the Barzani's (a.k.a the KRG) and the PKK (which by the way also has a supply deal with Iran) in return for attacking Iranian Kurdish rebel groups. The PUK and Gorran are more sympathetic to Iran and the PKK while the KDP is more tollerant (I would not use the word sympathetic) towards Turkey.
