On May 10th, the acting Secretary of Defense Pat Shanahan approved a plan to transfer $1.5 billion from various Department of Defense (DOD) programs to fund the border wall, following President Donald Trump's February declaration of a national emergency to redirect spending for the project. Shanahan reportedly told Congress that the funding is being sourced from a "variety" of programs within the Department of Defense.
DOD programs losing funding include a chemical demilitarization program, Air Force missile programs, and the "Blended Retirement System," a program introduced in 2018 that combines the traditional military pension with the government's Thrift Savings Plan. The largest contributor of redirected funding will be the Afghan military: $604 million in DOD funding will be reallocated from the Afghan National Security Forces to the wall.
A 2018 report from Global Security Review estimates that the Afghan National Security Forces require $4.5 billion a year to operate. Much of this funding comes from the Department of Defense and international coalition allies.