(S (S (NP (BASENP (DT The) (NN government) (POS 's)) (BASENP (ADJP (RBS most) (JJ important)) (NN duty))) (VP (VBZ is) (S (VP (TO to) (VP (VB ensure) (NP (BASENP (DT the) (NN security)) (PP (IN of) (BASENP (DT all) (NNPS Canadians))))))))) (PERIOD .))