There are 29 member nations that make up NATO. Each member country has a permanent delegation at NATO's headquarters in Brussels. An ambassador heads up every nation's delegation and this ambassador represents his/her government in NATO's consensus decision-making process. Kay Bailey Hutchison is the current U.S. ambassador to NATO.
Each member nation has a seat on the North Atlantic Council (NAC), the main political decision-making body at NATO. The NAC is chaired by the secretary general and meets at least once a week or as necessary. The Nuclear Planning Group has similar authority to the NAC, but only on matters regarding nuclear policies [source: NATO].
If decisions of the alliance have military implications, the Military Committee is brought in. The Military Committee is NATO's senior authority on all things military. It's the oldest committee in NATO after the NAC, and its primary responsibility is to advise the NAC and the Nuclear Planning Group, making it an essential link between NATO's political decision makers and its military structure. The Military Committee also prepares long-term assessments on countries and areas considered risks to NATO's interests.