WASHINGTON, May 14 (UPI) -- A State Department official told Congress on Thursday that NATO remains a critical deterrent to Russian aggression, and he reaffirmed U.S. support for the Baltic states. That reassurance comes as the war in Iran has resulted in delayed U.S. weapons shipments to Europe and the Pentagon canceling a planned deployment of 4,000 troops to Poland. "The U.S. remains firmly committed to standing with our Baltic allies," Christopher Smith , deputy assistant secretary in the