Abstract: The role of the North Atlantic Treaty Organization (NATO) on the United States’ national security policy has expanded significantly since its origins in the Cold War. The expansion of NATO became predominant after the September 11th terrorist attacks, because the institution helped unify its members into fighting against terrorism. As a result of its expansion, less conflict has arisen because the countries that join develop a stronger trust and can better cooperate with other members. Despite its benefits, opposition to the expansion of NATO exists, primarily from Russia. While it is important to keep in mind Russia’s security concerns, as well as the differences between NATO and Russia, the common interests between them should also be recognized, from nonproliferation and counter-terrorism, to border controls and counter-narcotics. In continuing the transformation of NATO away from being primarily a military pact, its members should emphasize its value as a forum in which political ideas can be exchanged. Diplomatic measures should be taken and increased among the members of NATO so that opposition to NATO expansion can ultimately become a thing of the past.