(S (S (BASENP (JJ Australian) (NNP Prime) (NNP Minister) (NNP John) (NNP Howard)) (VP (VBZ has) (VP (VP (VBN attacked) (BASENP (NNP US) (JJ presidential) (NN candidate) (NNP Barack) (NNP Obama))) (PP (IN on) (NP (BASENP (PRPD his) (NN pledge)) (SBAR (S (VP (TO to) (VP (VB introduce) (NP (BASENP (DT a) (NN bill)) (SBAR (WHNP (WDT that)) (S (VP (MD would) (VP (VP (VP (VB withdraw) (BASENP (JJ American) (NNS troops))) (PP (IN from) (BASENP (NNP Iraq)))) (PP (IN by) (BASENP (NNP March) (NN 2008))))))))))))))))) (PERIOD .))