They may not leave their base, unless on patrol or another mission. They could be prosecuted as traitors if found acting against US interests. And they are not allowed contact with relatives or old friends.
When Farhamg's three nieces, whom she had not seen since she left Afghanistan as a 14-year-old bride 30 years ago, came to the gate of the base one day to greet her, they were turned away.
"My kids think I have lost my mind," admits Farhamg, who today has siblings, grown children, three grandchildren, and a home back in California. "And I am pretty tough ... but when I got here, I cried all the time. I missed everyone and I felt locked in."
The daughter of a well-to-do Kandahar family, Farhamg was brought to the US by her first husband, a cousin who had secured a green card. They lived in Queens, where he worked as a doctor's assistant and she went to beauty school. They had four children before opening a pizzeria. Slowly, she managed to bring most of her family over to join her.
When Farhamg's husband died, she moved her family to Las Vegas for a decade before setting off for California with her second husband, an Afghan widower she met near the slot machines and married, in a traditional green Afghan wedding dress, at Graceland Chapel.
Post 9/11, her eldest son, a high school teacher in San Diego, began dabbling in extremist Islam, traveling to Afghanistan and Saudi Arabia for militant training. Five years ago, he was killed in Mexico. While the case was never solved, Farhamg believes he was murdered by his own mentors and friends after refusing to carry out a suicide attack.