NATO Enlargement: Senate Advice andConsent

Michael John Garcia
Legislative Attorney

On July 21, 1949, the Senate gave its advice and consent to ratification of the North Atlantic Treaty. That treaty bound twelve states—the United States, Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, and Great Britain—in a pact of mutual defense and created the North Atlantic Treaty Organization (NATO). NATO now has a membership of 28 states. This enlargement has occurred gradually—Greece and Turkey joined in 1952; the Federal Republic of Germany in 1955; Spain in 1982; Poland, Hungary, and the Czech Republic in 1998; Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia in 2004; and Albania and Croatia in 2009. 

Each enlargement of NATO has raised the question of whether Senate advice and consent is necessary. The North Atlantic Treaty itself simply provides that any enlargement must be approved by all of the member states "in accordance with their respective constitutional processes." In giving its advice and consent to the treaty in 1949, the Senate did not impose a formal condition regarding its participation in future enlargements of NATO. But it did obtain an explicit commitment from the Truman Administration that all proposed enlargements of NATO would be submitted to the Senate for its advice and consent. That commitment has been honored. All proposals to enlarge NATO have been submitted to the Senate; and the Senate has invariably given its assent (although in recent times subject to a number of conditions). 

This report describes the provisions of the North Atlantic Treaty and of the original Senate debate in 1949 pertinent to enlargement and the procedures that have been followed for each subsequent enlargement proposal. It also discusses what the Senate did with respect to the reunification of Germany in 1990 and the implications of that event for Germany's membership in NATO. The report will be updated as needed.


Date of Report: January 15, 2010
Number of Pages: 13
Order Number: RL31915
Price: $29.95

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