Obama is sending a contingent of US special forces to assist the Syrian Kurds.

This seems like a good idea to me. A limited amount of help for the Kurds could make a big difference for them in fighting PISSI, while avoiding the harm that a large US intervention force would do.

If the Kurds can cut off PISSI from the Turkish border, it would crimp PISSI's funds (obtained by selling oil) and recruitment (foreign recruits come through Turkey).

Obama should ask Congress for approval of the US intervention against PISSI. I expect he would easily get approval. The point is to maintain the system of checks and balances.