It is reportedly planning to dismantle the outposts in a single day to minimize the violence and bad PR that marred the last major evacuation, in 2006.
Proponents of the plane had argued for preserving jobs in the name of national security.
Halfway to President Obama’s deadline, basic aspects of the closure are undecided.
The date for closure is still January, but deciding which detainees are dangerous and which should be prosecuted is difficult.
In public speeches and back-room arm-twisting, the president is still pushing to have a bill done as soon as possible. But his real deadline is the end of the year.
The senator said healthcare would be Obama's 'Waterloo' – if Obama lost, it would break him. Now, Obama is using the comment as an example of crass Beltway obstructionism.
The Republican congressman and Afghan war veteran is a moderate who has worked across the aisle.