It might mean fewer dead Americans, though.

This month has seen the smallest number of Americans killed in Iraq than any other month since March 2006. But the reasons may have less to do with progress in the war than with the way we're now fighting it.

Just 29 U.S. military personnel have died in Iraq in October so far—down from 65 in September, 84 in August, 78 in July, 101 in June … You get the picture: Fewer, in most cases far fewer, than half as many American soldiers have died this month than in any previous month all year.

However, some perspective is warranted. First, all told, 2007 has been a horrible year for American lives lost in this war—832 to date, more than the 822 lost in all of 2006, and, by the time the year ends, almost certainly more than the 846 killed in 2005 or the 849 in 2004.

True, this month marks the second month in a row in which fatalities have declined, and that's noteworthy. But it doesn't quite constitute a trend, much less an occasion for celebrating.

Second, the slight increase in American fatalities this year, up until recently, is no surprise. When Gen. David Petraeus, the U.S. commander in Iraq, announced a shift to a counterinsurgency strategy—in which his troops would move more aggressively against militias and live among the Iraqi people instead of hunkering down in their massive bases—he acknowledged that the strategy carried risks and that more American casualties would be one of the consequences.

So, what accounts for the decline in American deaths since the summer? It's hard to say for sure, but one little-reported cause is almost certainly a relative shift in U.S. tactics from fighting on the ground to bombing from the air.

On Sunday, U.S. soldiers were searching for a leader of a kidnapping ring in Baghdad's Sadr City. The soldiers came under fire from a building. Rather than engage in dangerous door-to-door conflict, they called in air support. Army helicopters flew overhead and shelled the building, killing several of the fighters but also at least six innocent civilians. * (The bad guy got away.)

In other words, though the shift means greater safety for our ground troops, it also generates more local hostility. Striking urban targets from the air inevitably means killing more innocent bystanders. This makes some of the bystanders' relatives yearn for vengeance. And it makes many Iraqis—relatives, neighbors, and others watching the news of the attack on television—less trusting of the American troops who are supposedly protecting them.

In a conventional war, these consequences might be deemed unavoidable side-effects. But in a counterinsurgency campaign, where the point is to sway the hearts and minds of the population, wreaking such damage is self-defeating.

The U.S. Army's field manual on counterinsurgency, which Gen. Petraeus supervised shortly before he returned to Iraq, makes the point explicitly: