Does NATO functions as a useful tool for the US in order to continue to promote its values and principles?

In my opinion, NATO is a vital alliance, important for the maintenance of collective security, peace and stability of the world. NATO has become an important political institution advocating its commitment to democratic values with its system of to resolving emerging conflicts through its practice of consensus ensuring peace. NATO has been successful in fulfilling its member’s security over the years. The cost of security would be a burden to “weaker” nations that would not be able to secure themselves individually. This is the reason why I think that the alliance will not come to an end as its members will continue to support it as NATO re-evaluates its goals and its ability to respond to the new enemies, challenges and treats collectively. Another important task of NATO to contribute to its legitimacy is its role in international humanitarian assistance in disaster-stricken areas.
NATO’s expansion to include countries of the former Warsaw Pact (former adversaries) has been controversial as some critics will argue that their admission to the alliance would jeopardize American-Russian relations. However, I believe that in expanding, NATO strengthened the security of its members and partners as it broadened its area of influence and helped these countries to reform and progress towards democratization and modernization contributing to the overall stability of Europe.
I also agree that the US interest and agenda is a very influential force in actions taken by NATO. I also believe that it will always exist a leading force in all organizations and institutions as they are operated by people with its own interest and bias. However, the US has been assumed the role of world leader since World War I and it will continue to act as the leader unless other power assumes its role.
The recent crisis is Libya is an example how NATO continues to play an important role in the international arena as it is the only military organization capable of supporting UN Security Council resolutions.