In southern Afghanistan, concerns about what comes next GARMSIR, AFGHANISTAN - On the wall of his office in this district's Marine headquarters, where other commanding officers might display photos of children and wives, Capt. Devin Blowes keeps a roster of bearded men whose names he's recently learned to pronounce. They are the same tribal elders Blowes's predecessors relied on during some of the bloodiest battles of the war. Now, as the Marines draw down from southern Helmand province, these men will determine the future of Garmsir. Tribal leaders are the backbone of this strategically vital region near Afghanistan's southern border with Pakistan. If they refuse to support the government after NATO forces leave, U.S. officials say there's a good chance the Taliban could make a vigorous return. But if traditional leaders present a united front against the insurgency, bolstering the legitimacy of the Afghan army and police, officials contend that a beleaguered Taliban won't be able to reconquer the district. Many tribal elders are still on the fence, engaging both the Taliban and the Americans just as the Marines complete their most dramatic withdrawal to date. More than half of the corps" 17,000 troops will leave Helmand by the end of September. A year ago, they were dispersed across more than 60 bases and outposts in Garmsir alone - a measure of the importance they placed on beating back the insurgency in what was once a Taliban haven. By August, the Marines were down to three. That swift departure has made some of the elders on Blowes's wall nervous. He has sketched a red dot next to those who "play both sides" - men who shake his hand in district meetings but express doubts about the prospect of a post-Marine Helmand, hedging their bets by supporting the Taliban. He has sketched a blue dot - a sign of trust and confidence in a district known for sordid alliances and obfuscation - next to only one face: a willowy elder from the influential Alizai tribe named Amir Shah Jan. Since the Marines converged on southern Helmand in 2009, Jan has offered crucial guidance, often at his own peril. When his son was nearly killed by a suicide bomber, the Marines helped provide medical treatment. Last year, they facilitated his appointment as a local police commander. When he delivered information about the insurgency, officers listened carefully and often made arrests. Like other elders here, Jan is a key conduit to thousands of residents who are more conscious of the district's tribal hierarchy than they are of the area's newly installed political leadership. Jan has long said that he needs the Marines for security. But the Marines might need him more than he needs them. If they can't prevent the dot next to his picture from changing from blue to red, they risk losing hard-fought gains. Head start against insurgency On paper, it looks as if the odds are in favor of the U.S.-backed government. There are about 3,000 Afghan soldiers and police in Garmsir and only 150 or so hardened Taliban fighters, according to a U.S. intelligence estimate. Although Garmsir was once the scene of major violence, ambushes and firefights in the district have largely subsided. The Marines describe their gift to the Afghans as "white space" - a strong head start against the Taliban. It's a gift they know could be easily squandered.