The United States on Tuesday signed an agreement to base anti-missile interceptors in Romania under a NATO missile-defense plan. U.S. Secretary of State Hillary Clinton signed the pact in Washington with visiting Romanian Foreign Minister Teodor Baconschi and said the United States expected to deploy the interceptor missiles at a Romanian air force base in about four years. “The agreement we have just signed will position Romania as a central player in NATO’s evolving missile-defense capability,” Clinton said, noting that the treaty still must be ratified by the U.S. Senate. “With this missile agreement, we are jointly building a safer, more secure future for us all.”