(S (S (PP (IN On) (BASENP (DT the) (NN announcement))) (COMMA ,) (S (BASENP (NN senior) (NNP Obama) (NNS staffers)) (VP (VBD explained) (SBAR (SBAR (IN that) (S (NP (BASENP (NNP Ryan) (POS 's)) (NN selection)) (QT (DQL ``) (VP (VP (VBZ makes) (ADJP (JJ clear))) (SBAR (IN that) (S (BASENP (NNP Romney)) (VP (MD would) (VP (VB be) (NP (BASENP (DT a) (NN rubber) (NN stamp)) (PP (IN for) (BASENP (DT the) (JJ congressional) (NNP GOP))))))))) (DQR '')))) (CC and) (SBAR (IN that) (S (BASENP (DT the) (NN choice)) (VP (VP (VBZ provides) (BASENP (DT the) (NNP Obama) (NN campaign))) (PP (IN with) (QT (DQL ``) (BASENP (JJ clear) (NNS advantages)) (DQR '')))))))))) (PERIOD .))