Some of the most senior members of the original Taliban are from Helmand, but they now operate from across the border in Pakistan, enabling them to move back and forth, often out of the reach of coalition forces. Beyond its symbolic value, Helmand remains a focus of their attacks not only because it is the gateway to other southern provinces, but also because its fields produce the highest amount of opium in Afghanistan and its vast deserts sit on the main opium trade route. Increasingly, the Taliban have come to resemble a drug cartel as much as an insurgency, relying heavily on the profits from the opium trade to fund their fight.

Complicating the situation, officials in Helmand say, local strongmen are using their influence to plant their own men in provincial security jobs in outposts on the drug-trade route. Gen. Abdul Rahman Rahman, the deputy interior minister, said more than 90 percent of the police officers in Helmand were residents of the province and thus vulnerable to meddling and conflicting loyalties.

For example, if a commander is replaced because of incompetence or abuse, security officials say, he is apt to take hundreds of his men with him, leaving a hole in the area’s defense.

Political ties can also undermine security. When the brother of a powerful lawmaker who served as the security chief of the Garmsir district was fired recently over allegations that he was involved in the drug trade, the lawmaker organized protests in Lashkar Gah and Kabul. (One of the lawmaker’s nephews remains the head of counternarcotics in the province.)

Moreover, military goals pale compared with the allure of financial gain.

“The most important thing for the forces in Helmand is their own interests and business in the province — they are trying to get the amount of money which they have been told,” said Muhammad Jan Rasulyar, a former deputy governor of Helmand, referring to the widely held belief that commanders in lucrative posts pay higher-ups who help them get such jobs. “Differences between government authorities in Helmand made the Taliban stronger in the province, and this is the main reason for the increasing of conflicts. The authorities ward off each other instead of the enemy.”

The army itself has struggled to recover after suffering a record number of casualties in Helmand last year. Gen. Murad Ali Murad, the deputy chief of the army staff, said senior officers had tried to use the winter months to rebuild the 215 Corps. But the relentless pace of the fighting, in Helmand and in other parts of the country, derailed their efforts. New recruits with little experience were thrown into battle.