Via the Corner, I made the same point myself on Friday. Once you’ve stopped ISIS’s advance from the air and they hunker down in the cities they control, what then? Who’s going in after them? In Iraq, presumably, it’ll be the Iraqi army and the peshmerga, although I don’t know why the latter would care about territory outside Kurdistan and I don’t know how effective the former is even if the desire is there. In Syria it’s even murkier. We’re not sending in American infantry to be sniped at in the streets of Raqqa. The Saudis and Jordanians might do it, I suppose, but Arab monarchies prefer to have White House suckers do their fighting for them, especially on the ground. (“We don’t want this to look like an American war,” a U.S. official told the NYT, which is grimly hilarious given that these always, always end up being “American wars.”) The “moderate” Syrian rebels could do it except that (a) they, er, just declared a truce with ISIS in Syria, which is a teensy bit inconvenient for the White House’s “arm the moderates” narrative, and (b) apart from crazed superhawks like McCain and Lindsey Graham, literally no one thinks the “moderates” will be reliable or effective. Right? Point me to one impartial Syria expert who thinks somewhat-less-fanatic Syrian Sunnis are the rabbit waiting to be pulled out of Uncle Sam’s star-spangled top hat.

Not this guy:

There were not many moderates around two years ago, as I found in Al Bab then, and there are far fewer now. A year ago the town was overrun by ISIS and many of the young rebels joined the group; others who remained loyal to brigades affiliated with the FSA pulled out. The bulk of those, according to locals, hooked up with the Islamic Front, a coalition of Islamist militias who are the second largest fighting insurgent formation after ISIS. The front has close ties with al-Nusra…

“There are certainly moderates remaining,” says Jonathan Schanzer, a Mideast expert with the Washington-based think tank the Foundation for the Defense of Democracies. “The problem is that they are few in number and lacking in support. They have been marginalized by U.S., European, Turkish, and Arab policies that have only served to boost the presence and capabilities of the more radical factions. It’s unclear to me how Washington’s new approach can help reverse this trend in an urgent or expeditious manner—which is what is needed.”…

[N]ot only is the Obama administration going to find it hard to select rebel groups it can work with, it will also have the problem of persuading them to focus on ISIS at the expense of their struggle against Assad, and if the regime starts making up more ground, that in turn could ignite local Sunni anger to the benefit of the jihadists.

If we’re not going to kick down doors in Syria to hunt ISIS and the Saudis aren’t going to do it and the, cough, “moderate” Syrians aren’t going to do it, who’s going to do it? Right: Assad and his Iranian/Hezbollah friends, and they’ll be killing plenty of Sunni civilians along the way. That’s Engel’s point. It’s our sworn enemy in Damascus who obviously stands to benefit most from this U.S. offensive, and who has both the means and the motive to chase down ISIS inside Syria once it’s in disarray. Re-read that boldface part in the excerpt too, as it’s a superb gloss on Engel’s fears here. If ISIS’s grip begins to loosen in Sunni areas of Syria as the U.S. pounds them from the air, what are “moderates” more likely to do? Join with their hated enemy, the Shiite Assad, in stamping out ISIS, at which point Assad might turn around and attack the “moderates”? Or join with ISIS and fend off Assad in the name of keeping Iran’s Shiite death squads from cleansing those Sunni areas? Arguably, the more effective we are in damaging ISIS, the greater the risk that our “moderate” partner will turn on us and join the battle against the de facto U.S./Assad alliance. Engel sees it coming. Does the White House?

I’m going to guess no. Surreal exit quotation:

WH spox Earnest is "skeptical that ISIL is going to have a whole lot of success" building relationships with Syria rebels.

— Jennifer Bendery (@jbendery) September 15, 2014