 whether he will in fact remain committed to the alliance. James Goldgeier, Brookings Visiting Fellow. The U.S. Congress in last December in the passage of the National Defense Authorization Act, the NDAA, included a provision that a U.S. president can't withdraw from NATO without a two-thirds vote of the U.S. Senate or an act of Congress. This was a bipartisan effort to try to ensure that the United States would remain in NATO.