President Obama's latest decision on the war in Afghanistan, like the one he made after his long policy review in 2009, is a compromise that seeks to balance an assortment of political and bureaucratic pressures. The decision is certainly not derivable from any textbook on counterinsurgency. Neither is it derivable from any a priori conception in the mind of the president himself about the use of military force or the projection of American power. President Obama would like to remove sooner rather than later the burden that the Afghan War has become, even though it was a burden partly of his own making. That aspiration was reflected in the latter part of his speech, in which he spoke of the need to focus on nation building at home rather than nation building abroad. He probably agrees with the reasoning identified with Vice President Biden, according to which a much smaller U.S. military presence in the Afghanistan/Pakistan theater would be appropriate for dealing with remaining terrorist threats in the area. Being guided by that reasoning would mean a faster troop withdrawal than the president announced. A faster withdrawal would have been more in the national interest than what he did announce. But that would have met just too much pushback from other elements in his administration. The timetable Mr. Obama announced fully pleases no one, but it may be not far from the most that realistically could have been expected.

The compromise in Mr. Obama's earlier decision involved a surge of additional troops with a date for starting a withdrawal that was barely a year after the surge was complete. That's not enough time, according to the counterinsurgency textbooks, to accomplish much. By leaving the pace of the withdrawal unspecified, the president could wait until now to see how either the political or the military conditions may have changed in the interim. The conditions in Afghanistan have involved an increase in the number of Taliban that has paralleled the increase in U.S. troops. There also has been greater security in areas where the NATO forces have concentrated their efforts, but with little reason to believe that corners will be turned or lights will shine at the end of tunnels any time soon. The main change in conditions at home has been decreased support for continuation of the war, among members of both political parties.

At the time of the 2012 presidential election, the level of U.S. troops currently in Afghanistan will have been cut by a third. To those looking for withdrawal, Mr. Obama can say then that a withdrawal is well under way. Most of the cut in troops will have been taken late enough, however, to have little effect on the current fighting season in Afghanistan and only partial effect on next year's season.

The president used words in his speech that appropriately limit the definition of U.S. objectives in Afghanistan and leave himself room, when he gives his next speech on Afghanistan, to continue the withdrawal even when it becomes clear that more broadly defined objectives will not be attained. He placed emphasis on what the Afghan government should do without predicting what it will do. He said we have reason to believe progress will be made on the diplomatic front without predicting such progress. He said NATO forces have inflicted serious damage on the Taliban without venturing any judgment that NATO forces are winning against the Taliban.

Maybe after the 2012 election the president will more squarely acknowledge a couple of basic realities about the conflict in Afghanistan that he addressed only more elliptically in his current speech. One is that not even the current level of foreign forces will bring stability to that country. Another is that even if Afghanistan is not stabilized, that is not critical to U.S. national interests.