It will be a while, the US military tells us, before the success or failure of its Afghan offensive in Marja can be determined with any certainty. That says it all: a superpower will require weeks to seize control of just a single town in a vast country of thousands of villages and valleys. Centcom commander Gen. David Petraeus calls the Marja action "just the initial operation of what will be a twelve- to eighteen-month campaign" aimed at wresting power from the Taliban. It’s fair to ask, of course, Isn’t that what they have been trying to do for eight long years?

The Obama administration says that this time it’s different–that the addition of 30,000 troops to the long-running conflict will turn the tide against the Taliban. The surge, Obama’s advisers have long argued, will reverse the insurgents’ momentum and persuade the Taliban’s foot soldiers, and perhaps some of their leaders, to come to the bargaining table. General Petraeus tells us to expect high casualties among US and NATO forces.

Leave aside, for a moment, the problem that adding US forces creates more enemies, not fewer (dozens of civilians have been killed in recent US airstrikes, further enraging the Afghan public). The fact is, clearing, holding and building new social and political structures in Afghanistan, village by village and valley by valley, will take many years, if it can be done at all. Stretching ahead is a decades-long nation-building project that can’t be sustained politically, militarily or financially.

As we go to press, the US death toll is nearing 1,000. More than 600 NATO troops have died in a conflict that is increasingly opposed in Europe and straining the alliance; indeed, the Dutch government recently collapsed because of widespread antiwar sentiment. More than eight years into the war, neither the Afghan army nor the police are very functional. The warlord-ridden, corrupt government of President Karzai, returned to power last year after a rigged vote, has little credibility. And Afghanistan’s primitive economy, heavily dependent on the drug industry, will be troubled for decades. (One development to watch is the possibility that Pakistan, after decades of fostering, arming and training the Taliban, may be coming around. In recent weeks Pakistan has helped nab several insurgent leaders and shadow governors, and it appears that it is snatching up Taliban by the hundreds fleeing across the Afghan border.)

For Marja to be of any lasting significance, it must be followed quickly by a political settlement, regional diplomacy and implementation of effective Afghan governance. Otherwise, it will merely be a fleeting counterinsurgency footprint wiped away before long by a returning Taliban tide–and thus a testament to the futile sacrifice of American lives and resources for an ill-defined goal of the administration’s Af-Pak strategy.

All of this should be fertile territory for exploration in hearings on Capitol Hill. At the height of the war in Iraq, Democrats hectored President Bush with the question, What’s your exit strategy? It’s time for Congress to ask Obama the same question. March promises to bring a revival of peace activism. Progressive Democrats of America has launched a "Healthcare Not Warfare" campaign, and, joined by Code Pink and other groups, it has started a "Brown Bag Lunch Vigil" at Congressional offices across the country to educate politicians and the public about the costs of war. A revived US antiwar movement that unites with the growing one in Europe would be a powerful force for a negotiated solution and a drawdown of forces.