President Barack Obama moved a key foreign policy goal closer to completion Wednesday, signing ratification documents for a nuclear arms-reduction treaty with Russia. The new Strategic Arms Reduction Treaty (START), negotiated last year, limits each side to 1,550 strategic warheads, down from 2,200. The agreement also re-establishes a monitoring system that ended in late 2009 with the expiration of an earlier arms-control deal. Signing the documents at the White House, Obama was joined by Secretary of State Hillary Clinton, Defense Secretary Robert Gates, Senate Foreign Relations Committee Chairman John Kerry (Democrat from Massachusetts), and Richard Lugar of Indiana, the senior Republican on the committee. Russian President Dmitry Medvedev signed similar documents last week after the treaty was approved by the Russian legislature. The U.S. Senate approved the deal in late December after Obama and a wide variety of current and former government officials had lobbied for its passage. Ratification becomes final when the two countries exchange the signed papers. Clinton and Russian Foreign Minister Sergei Lavrov are scheduled to make the exchange this weekend when they meet in Germany on the sidelines of the Munich Security Conference.