I'm going to pull a saz here and argue we need an updated version of the international volunteer force during the Spanish Civil War, a "John Brown" Brigade if you will. It's clear actors organized along existing geopolitical lines are not going to be able to resolve this crisis. On the other hand a dedicated cadre of fighters organized along the same transnational lines as ISIS albeit with completely different goals and understanding of "solidarity" for the self-determination of Arab peoples, particularly religious minorities. The crisis won't be resolved by arming the FSA or the same tired groups based on the usual networks of local patronage.
It's clear some other actor must step forth and claim legitimacy by demonstrating a principled commitment to a new ideology that is both critical of state abuses of power in the region and the violent frothing at the mouth brutality of so-called "non-state actors" like ISIS. Perhaps this is a way we could reclaim some kind of principled international solidarity in the wake of the void left by the Arab Spring.
I'm in South Asia, but f**k if I was just standing around with my dick in the sand back in the midwest I'd consider providing logistical support and media organizing for such a campaign. Seriously, I actually do belive in ethical obligations to the oppressed of this world, even if they aren't being assaulted by typical Left bogeymen like US imperialism.
I'm as critical of US imperialism as the next guy, and I think the US's Gulf sub-monarchs have demonstrated their own compromised loyalties in stoking the fires of extremism while playing lapdog to the US. But it's clear that ISIS is a new phenomenon that transcends traditional ideological loyalties and political positions. It demands a creative response. The distinction between "pro-" and "anti-war" is completely useless in the current context.
History itself has no morality, it recognizes no victims, which is precisely why it's true meaning is only determined by the ethical commitments we have to each other.
EDIT: interesting thought: this could also provide another way of thinking about the Israeli-Palestinian issue, particularly by creating a new narrative of Christianity in the promised land that has been subjected to "separation walls" and Israeli fortifications; Bethlehem under siege, so to speak. People often forget for example that some of the leading Palestinian authorities and spokespeople have been/are Christian (Hanan Ashrawi, Rashid Khalidi, Edward Said, etc.) Which is not to say Palestinian Muslims don't count, but precisely the fact that they are treated as
minorities by Israel.
Again the question for the region isn't "Islam" as such but the ways in which majoritarian nationalisms and ideologies--whether Israeli, Saudi, Islamist--violently suppress minority communities throughout the region, whether Yazidi, Palestinian, Kurdish, and so on. A principled stand on this issue would shore up the legitimacy of any international solidarity movement to defeat ISIS and prevent it from subsumed under traditional US state-sponsored goals, which have been complicit in the current crisis (most obviously, the invasion of Iraq).