Paine's political influence was greatest in England. In intellectual terms, his Rights of Man was his greatest political work and was certainly the best-selling radical political tract in late 18th century England. Before Paine, British radicals sought a reform of Parliament which would grant to all men the vote for members of the House of Commons. In his Rights of Man, Paine abandoned this approach and, rejecting the lessons of history, maintained that each age had the right to establish a political system which satisfied its needs. He rested his case on the moral basis of the natural equality of men in the sight of God. Since government is a necessary evil that men accepted as a means of protecting their natural rights (cf. John Locke), the only legitimate government was that established by a contract between all members of society and one in which all men preserved all their natural rights, except the individual right to use force. Paine argued rationally that all men had an equal claim to political rights and that government must rest on the ultimate sovereignty of the people.