He was the author of A Critical Study of Nullification in South Carolina (1896).
He became prominent, politically, during the nullification excitement of 1832-1833, as a vigorous opponent of nullification, and from 1836 to 1845 he sat in the United States Senate as a Unionist Democrat.
It was due to his dependence on Charles V., rather than to any conscientious scruples, that Clement evaded Henry VIII.'s demand for the nullification of his marriage with Catherine of Aragon, and so brought about the breach between England and Rome.
He sided with the president in his nullification controversy with South Carolina and in his removal of the Indians from Georgia, but not in his withdrawal of the government deposits from the United States Bank.
No particulars of their life have been made public. In 1854 his wife left him, obtained a nullification of the marriage under Scots law, and ultimately became the wife of John Everett Millais.
Until 1832 there was only one party in the state, the Democratic, but the question of nullification caused a division that year into the (Jackson) Democratic party and the State's Rights (Calhoun Democratic) party; about the same time, also, there arose, chiefly in those counties where the proportion of slaves to freemen was greater and the freemen were most aristocratic, the Whig party.
Green, however, continued to edit it in the Calhoun interest until 1835, and gave vigorous support to that leader's nullification views.
Houston, Critical Study of Nullification in South Carolina (New York, 1896), is a concise, scholarly work.
Then the Troup faction under the name of States Rights party, endorsed the nullification policy of South Carolina, while the Clarke faction, calling itself a Union party, opposed South Carolina's conduct, but on the grounds of expediency rather than of principle.
Congress passed an act gradually reducing the duties to a revenue basis, and South Carolina repealed her nullification measures.