The military move will include 13,500 troops going into Kuwait due to sudden conflicts in that region. Iraq is a part of the conflicts that are suddenly arising, as the US military is relocating out of Iraq and there are concerns that Iran will start causing trouble. Peace in the Middle East is not exactly winning. Instead, there are still hidden pockets of those who wish to create uprisings in their own country, as well as in the US. It was decided by a study of Foreign Relations that six of the nations that the US has agreements in would approve the military to stay in the event that they are needed again to provide peace.
Kuwait has suffered an internal political issue, while Saudi Arabia has suffered the loss of Prince Nayef. These issues could give rise to political leader changes that might create uprisings and thus require the military to relocate from the US to the Middle East. This is why the general thought of leaving some troops in countries that are not opposed to troops being in local bases has occurred. There are about 15,000 troops in Kuwait at the moment, but these numbers will lower once troops start going home and being replaced with a new set of personnel from stateside.