WASHINGTON  Before 10,000 troops marched through central Helmand Province to wrest control of a small Afghan town from a few hundred entrenched Taliban fighters, American officials did something more typical of political than military campaigns: they took some polls.

Perhaps no other feature of the offensive now under way in and around the town, Marja, speaks so clearly to its central characteristic: it is a campaign meant to shift perceptions as much as to alter the military balance, crush an enemy army or seize some vital crossroads.

The polling was aimed at understanding what local residents wanted; how they viewed local security; what they thought of the Americans, the Taliban and the foreign jihadis fighting for local control; and what might give them confidence in the central government in Kabul.

Whatever the limitations of this opinion sampling  what is the margin of error when there are whole neighborhoods where it is deadly to knock on doors?  what the commanders learned helped shape the entire campaign. Among other things, those living in the area still harbor some friendly feelings for the Americans, remembering how years ago they built dams in the region, and strongly favor an effort to oust the Taliban.