He continued to occupy a prominent place in parliament, where he advocated free trade, the relief of the Catholics from penal legislation, and the reform of parliament. He was one of the very earliest politicians to recognise the soundness of Adam Smith's views on trade; and he quoted from the "Wealth of Nations", adopting some of its principles, in his "Commercial Restraints of Ireland", published in 1779, which Lecky pronounces one of the best specimens of political literature produced in Ireland in the latter half of the 18th century.