Douglas London, a 34-year veteran of the CIA, said intelligence operations in Afghanistan are dependent on the large military presence the US has kept in the country.
"The US intelligence presence and ability to collect information depends on the military's infrastructure across the country," said London.
"As the US presence diminishes, and with it collectors who need to physically acquire intelligence on the ground, so does our visibility," he added. "That human intelligence comes from sources on the ground who can be regularly met. How many can travel to Kabul, let alone outside the country?"