Why Obama is Sending More Troops to Afghanistan Now

President Obama was initially wary of agreeing to this week's announced deployment of some 17,000 extra troops to Afghanistan, according to administration sources. He preferred to await the outcome of a full-blown review on U.S. strategy in the country which could land on his desk in six weeks or so. But with critical elections looming, even that delay wasn't acceptable.

Already postponed from May because the Taliban insurgency has prevented voter-registration across most of the south and east of the country, Afghanistan's national elections have now been set for early August. This vote's success is critical to Washington's strategy in Afghanistan. And it won't be unless U.S. troops can bring security to the most threatened areas.

With the addition of 17,000 extra troops, starting in late May, the U.S. total in Afghanistan will reach 55,000. Add the 32,000 non-American NATO troops already in the country, and the total Western troops in Afghanistan will hit 87,000—the highest total yet in the seven-year war. And thousands more are expected to be required by year's end.

Military units can't be turned on like a spigot. Most need weeks to gear up—and, ideally, months to train up—for deployment; and then more weeks, once they're in the country, before they're truly knowledgeable about their allotted territory.

So, at a session in the White House last week, Defense Secretary Robert Gates and Adm. Mike Mullen, chairman of the Joint Chiefs, made their case to the president. The need for more troops to safeguard the elections couldn't wait for the review.

The destinations of those 17,000 extra troops are no secret. The first to leave, 8,000 Marines of the 2nd Marine Expeditionary Brigade out of Camp Lejeune, N.C., will be guarding the southern approaches to the capital, Kabul. Taliban forces now cluster within a few miles of the city; and last week demonstrated—with simultaneous suicide-bomb attacks on three government centers in Kabul—that they can ravage the city at will.

The second tranche of U.S. reinforcements—4,000 soldiers of the 5th Stryker Brigade, 2nd Infantry Division, based at Fort Lewis, Wash.—will set off in late July. That's perilously close to the August elections. But the hope is that, by then, the Marines will have pushed the Taliban back far enough from Kabul to allow these new forces to take up the security role in the capital, while the Marines pursue the Taliban deeper into the south-eastern border areas of Afghanistan.

The Stryker armored vehicles—fast, almost silent, carrying a squad of nine, and equipped with communications and navigation gear enabling their crew to speed through even strange cities—proved their worth as rapid-responders in the urban warfare in Iraq, starting in Mosul in 2004. But they're not designed to operate in the rugged terrain of Afghanistan. For that, helicopters are needed. So one of the "support elements" also heading out there later this year will be the helicopters of the 82nd Airborne Division's combat aviation brigade: 2,800 troops with more than 100 helicopters, mostly Apaches, Blackhawks and Chinooks. (This is a swift return for some: one battalion of this brigade was in Afghanistan as recently as 2007.)

Even with back-up by the 82nd, though, U.S. forces will still be critically short of helicopters. NATO forces are even less well-supplied. Shortage of air-mobility is a major constraint on operations inside Afghanistan. But it's symptomatic of the more general operational situation in the country: too few troops trying to bring security over too wide an area. This "troop-to-space" ratio will be only marginally bolstered by these latest deployments.

The upshot of this troop-shortage has been that NATO forces have relied ever more heavily on air-strikes (which the United States has to carry out, since other NATO forces lack air-support). The consequences are revealed by the latest report of the United Nations mission in Afghanistan. The U.N. reckons that just over 2,000 Afghan civilians were killed in the fighting there last year—a 40 percent increase over 2007. Worse, the U.N. report tallies more than 800 of these as killed by U.S., NATO and Afghan government forces—a 30 percent increase over 2007. Worse still, the U.N. estimates that two in three of these (around 550) were killed by allied air-strikes. That's uncomfortably close to double the toll from air-strikes (around 320) in 2007, which in turn was approaching three times the toll (around 120) in 2006.

It remains true that, by U.N. reckoning, more than half the civilian casualties in Afghanistan last year were inflicted by the Taliban and other anti-government groups. Nevertheless, casualties from U.S. air-strikes are a hugely sensitive issue. (So sensitive that the British have flown back to London, to face possible criminal charges, an Army officer alleged to have leaked some statistics.) Afghan President Hamid Karzai has repeatedly called for Coalition forces to re-think their use of air-power.

The latest polling data explains his concern. Barely one in three Afghans now say that people support the U.S. and NATO forces—half the numbers who did in 2006. Air-strikes appear to be one of the major reasons behind this precipitous drop. Three in four Afghans polled called the air-strikes unacceptable. "The international coalition in Afghanistan is losing public support, one fallen civilian at a time," says a new study from CIVIC, a U.S.-based group which monitors civilian casualties in Afghanistan.

The U.S. military is acutely aware of this. Adm. Mullen sounded the alarm earlier this week in The Washington Post: "Each civilian casualty for which we are even remotely responsible sets back our efforts to gain the confidence of the Afghan people months, if not years. It doesn't matter how hard we try to avoid hurting the innocent; and we do try very hard. … In the end, all that matters is that, despite our best efforts, sometimes we take the very lives we are trying to protect. You cannot defeat an insurgency this way." But absent enough troops to operate without the continued back-up of air-strikes, the U.S. military will continue to incur civilian deaths, with the strategic consequences Adm. Mullen describes.

In a TV interview Tuesday after his decision to send these extra 17,000 troops to Afghanistan, President Obama said: "I am absolutely convinced that you cannot solve the problem of Afghanistan—the Taliban, the spread of extremism in that region—solely by military means." That's true. It's equally the case, unhappily, that only the military can provide the security needed to put in place the other pillars of a counter-insurgency campaign: jobs, civic works and the spread of good government. Unless his strategic review comes up with some magical formula for success—which seems implausible—Obama will likely find that a commitment of far more than 17,000 troops is going to be needed by the end of this year.