I think we can collaborate with Iran on dispelling this ISIS threat but I have no illusions, as long as Iran has an Ayatollah, its government will continue to rely on its Anti-Americanism and Anti-Israel as means of self-preservation of the 1979 Islamic Revolution. However, for now they will put that on the back burner for the more immediate threat we face. We can maintain short-term relationship with an rational enemy(Iran), but in the long term we might as well purchase their hegemony like we did when we decided to invade Iraq and toppled Saddam. As for Assad, We should distance ourselves with that regime and keep reaching out to remaining Free Syrian Rebels . Our collaboration with His benefactor, Iran should be the only contribution we make for the Assad Regime. We should just let Assad regime bleed more blood and treasure and let Russia throw more of money at him until that regime is spent.
Wrong. We did Iran a favor by taking Saddam out.
It was Iran that started the up rising in 03 with financial support to Muqtada Al Sadar in the south in Najaf.
Plus the Saudi's won't support us working together with a Shiite dominated state of Iran.