(S (S (PP (VBG According) (PP (TO to) (NP (BASENP (JJ senior) (NNS officials)) (PP (IN in) (BASENP (DT the) (NNP Obama) (NN administration)))))) (COMMA ,) (S (BASENP (DT the) (NNP U.S.)) (VP (VBZ is) (S (VP (TO to) (VP (ADVP (RB significantly) (CC and) (RB permanently)) (VP (VP (VP (VB reduce) (NP (BASENP (PRPD its) (NN stockpile)) (PP (IN of) (BASENP (JJ nuclear) (NNS weapons))))) (PP (IN by) (NP (BASENP (NNS thousands)) (PP (IN of) (BASENP (NNS weapons)))))) (PP (IN as) (NP (BASENP (NN part)) (PP (IN of) (NP (BASENP (DT a) (JJ major) (NN rethinking)) (PP (IN of) (BASENP (JJ American) (JJ nuclear) (NN policy)))))))))))))) (PERIOD .))