Ever since the weird, non-war against ISIS began, we have heard loud boasts from the Obama administration about how many fabulously expensive coalition force airstrikes we’re conducting. And yet, the Islamic State remains on the march in Iraq and Syria and is confident enough to launch a new campaign for control of devastated post-Obama, post-Clinton Libya.

A big part of the answer to why ISIS has not been diminished is provided by The Hillwhich reports U.S. lawmakers are frustrated by rules of engagement that call for “zero civilian casualties.”

“While officials say they can never be absolutely certain of who’s on the ground, U.S. and allied forces are refraining from airstrikes against ISIS if there’s a risk of even one civilian casualty,” says the report. It notes—with what one might call severe understatement—that such rules of engagement are “adding a new wrinkle to the U.S. bombing campaign in Iraq and Syria, which is already operating without the help of ‘spotters’ on the ground who can call in strikes on known ISIS targets.”

Senator John McCain called it nuts in so many words, saying the air campaign against ISIS is “totally ineffectual” because “seventy-five percent of those combat missions return to base without dropping a weapon.”

The military conceded that McCain’s figure is accurate but claims it is not far out of line with previous air campaigns. However, retired Air Force Lt. General Dave Deptula said the zero-casualties restriction goes far beyond the normal standard of ensuring that “reasonable measures be taken to avoid collateral damage and civilian casualties.” He described the pace of the anti-ISIS campaign as a “drizzle” of airstrikes.

Deptula and Rep. Martha McSally (R-AZ), herself a retired Air Force colonel and pilot, are quoted making the point that ISIS is responsible for the death of people it uses as human shields, and if they know we are willing to take that responsibility off their shoulders, they will happily line up civilians around every position and neutralize our air power. That seems to be a fair description of what they have been doing so far.

The argument in favor of the zero-casualties policy is that collateral damage makes it harder to win the hearts and minds of the local population after the war is over. How are we supposed to get a shot at winning hearts and minds if we leave ISIS in control of captive cities for years, working the population over with their brutal fascist programming techniques? Will the people subject to their depredations thank us for fighting them half-heartedly, in an extreme effort to avoid collateral damage, leaving that carefully-protected civilian populace prey to torture, rape, and murder? Is a liberated northern Iraq with some hard feelings about the bombing campaign launched in support of their own government, against a brutal invasion, worse than having a “caliphate” of pure evil sprawled across Syria, Iraq, and Libya?

Of course, because this is an Obama administration story, no one is clear about who set the “zero civilian casualties” standard. The Hill quotes both a senior military official and Defense Secretary Ashton Carter saying it came from foreign commanders, although Carter said he is not really sure. “I think the only limitation [that] the people managing the coalition air campaign have — and this is a coalition judgment, not just a U.S. judgment — is to try to avoid civilian casualties,” he stammered to the House Armed Services Committee last week.