That is a possibility..
Ironically, if ISIS is able to hold on until a Republican takes office in 2016 (or a less willfully incompetent Democrat), then when ISIS does go down, the Kurds would be more likely to expect help from the US against Iran/Shiites, if such a move was made.
Once the Kurds prevail, the Iranians will be able to turn their full attention to Syria — and they’ll have what’s left of ISIS in Syria entirely in their fold by then.