Republican political theory takes its starting point from a long-established tradition of thinking about politics (Pocock 1975). The republican tradition is associated with Cicero at the time of the Roman republic; with a number of writers, pre-eminently Machiavelli – ‘the divine Machiavel’ of the Discourses – in the Renaissance Italian republics; with James Harrington, Algernon Sydney and a host of lesser figures in and after the period of the English Civil War and commonwealth; and with the many theorists of republic or commonwealth in eighteenth-century England, the United States and France. These theorists – the commonwealthmen (Robbins 1959) – were greatly influenced by John Locke and, later, the Baron de Montesquieu; indeed they claimed Locke and Montesquieu, with good reason, as their own. They are well represented in documents like Cato's Letters (Trenchard and Gordon 1971) and, on the American side of the Atlantic, the Federalist Papers (Madison et al. 1987).

The commonwealthmen helped to shape habits of political reflex and thought that still survive today. Their distinctive refrain had two parts: the cause of freedom rests squarely with the law and the state – it is mainly thanks to the constitution under which they live that people enjoy freedom; but the authorities are also an inherent threat and people have to strive to ‘keep the bastards honest’.