There is no problem except, if they can prove the US is funding and arming these miscreants, we could end up tussling with the bear. It could get ugly. It already is.
If they can prove that the US is aiding ISIL, we should execute everyone involved ourselves. Just following orders is no excuse for treason.
If Obama acts quickly, he can support ISIS with Navy air cover and covert ground troops, while continuing the gun & MANPAD running through State, and eliminate Assad like he did Qaddafi.
That'll fix all the problems in Syria.
Like Libya.