http://www.reuters.com/locales/newsA...toryID=4492902
"It does not appear that an aircraft as advanced and expensive as the
Raptor is required to address near-term defense threats," Christopher
Bolkcom, chief military aviation anlayst of the non-partisan
Congressional Research Service, told a panel of the House Armed Services
Committee.
....
Bolkcom said the Raptor's 540-nautical mile unrefueled combat radius
dictated it operated from forward bases -- another drawback for a
Pentagon facing potential conflict in distant lands with perhaps scant
bases nearby from which to operate.

Nothing can stop the US Air Force, once they have a permission slip.

-HJC