May 24 (UPI) -- The United States on Sunday blamed the collapse of a U.N. nuclear nonproliferation conference on what it called some countries' inability to take Iran's threat to global nonproliferation seriously. The nearly monthlong Review Conference of the Parties to the Treaty on the Nonproliferation of Nuclear Weapons ended Friday without consensus on an outcome document, which reviews implementation of the Cold War-era pact and sets recommendations and commitments for its 191 state