From Owen Chadwick's magisterial The Victorian Church Vol. 1 (1966), 300.
Manning and Newman were contrasting types and leaders of Anglicans attracted towards Rome. Newman was a divine, Manning a churchman. Newman looked for theological truth and found it in that church which, he came to believe, represented with least unfaithfulness the doctrine and ethos of the first Christian centuries. Manning knew that the church possessed the truth, but the English establishment allowed the state to adulterate the possession. Newman left the Church of England because it spoke to his conscience with stammering lips. Manning left the Church of England because it let a non-Christian state within its borders and surrendered its guardianship of truth to state officers. Newman left the Anglicans because they were Protestants, Manning because they were established.