(S (S (NP (BASENP (NN One)) (PP (IN of) (BASENP (DT the) (JJ key) (NNS issues)))) (VP (VBZ is) (NP (NP (BASENP (NNP Sinn) (NNP Fein) (POS 's)) (NN recognition)) (PP (IN of) (NP (NP (BASENP (DT the) (NNPS Police) (NNP Service)) (PP (IN of) (BASENP (NNP Northern) (NNP Island)))) (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBD replaced) (BASENP (DT the) (JJ controverisal) (NNP Royal) (NNP Ulster) (NNP Constabulary)))))))))) (PERIOD .))