How to lose a war by splitting the difference.
The downside of this approach, of course, is its opportunity costs: Decisive action in Kandahar precludes decisive action elsewhere. Helmand and the volatile provinces in the east would be left to fend for themselves until the operations in Kandahar were complete. There would likely be few demonstrable regional synergies in the short term, either--the Kandahar "ink spot" would not be linked to any other save that created by the new rurally focused brigade in Kandahar, which could presumably provide support to the population center of Tarin Kowt, north of Kandahar in Oruzgan province. But since the Dutch battalion in Oruzgan is scheduled to leave next year, larger or longer-term local success would be uncertain. Nevertheless, an all-in approach to Kandahar would have good prospects for achieving at least a localized example--and arguably the most decisive example--of sustainable security.
This would be, to force an Iraq analogy, akin to having succeeded only in Anbar in 2007, without the follow-on successes in the Baghdad belt, in the capital, in Basra, and in chasing al Qaeda and the insurgents northward. So even if an incomplete surge could chalk up some successes, other risks would continue to rise. Violence has long been festering in northern Afghanistan, with the Taliban resurgent there and election tensions accelerating the trend; Kunduz and Mazar-e-sharif are on the White House "Top 10" list of cities to be secured, but it's hard to see how, with a semi-surge, anything more could be done there. Likewise, in the west, Herat is critical but has been all but neglected heretofore.
Officers in Afghanistan ruefully observe that you can't have an ink-spot strategy without enough ink. A half-surge would increase the amount of ink, but Afghanistan is a large and dry piece of paper; McChrystal Lite would make it hard to connect the dots. It would also be hard to synchronize the effort with the nascent counterinsurgency campaign in Pakistan. It's good news that the Pakistani Army is pushing into South Waziristan, but unless there is pressure across the border in Khost and greater Paktia, the likelihood of Pakistan advancing against the Haqqanis is negligible.
The biggest problem, though, is that a half-surge cannot produce a meaningful result in a timely manner; we should remember that the McChrystal plan proceeds from his assessment that the next year--several months of which have already been lost--is critical to regaining the initiative from the Taliban.
Time matters not only in Afghanistan, but also in Pakistan and, most of all, in Washington and across America where, absent some sign that the war can be won, political and public support is increasingly shaky. If McChrystal Lite is problematic from a battlefield perspective, it's worse from a strategic and political standpoint.
A clever commander like McChrystal and the capable troops he leads will no doubt figure out how to make the most of what they've got. But a half-surge would seem to cut their prospects of winning by more than half.
Tom Donnelly is the director of the American Enterprise Institute's Center for Defense Studies. Tim Sullivan is the Center's program manager and a research fellow at AEI.