In this article, Michael Zuckert traces the development of the various thinkers and groups who are known as the “Radical Whigs.” United in their opposition to centralized and absolute government, the Radical Whigs opposed Charles II and the Stuart kings, and strove to prevent the Catholic James from becoming king. While some of the Whigs advocated legal methods for this prevention, others (such as Algernon Sidney) advocated violent action. But with the Whig ascendancy in the Glorious Revolution, many Radical Whigs became disillusioned with the contemporary Whig leadership. Cato’s Letters, an anti-absolutist newspaper series, typified this second-wave Radical Whig philosophy. Second-wave Radical Whigs held to a social contract theory, inspired by Locke, in which men enter into society in order to preserve and secure their natural rights. Moreover, Cato’s Letters attempted to draw out the concrete implications of this Lockean philosophy in the areas of religion, constitutionalism, and economy, always championing freedom and decrying absolutism in any form. Most Radical Whigs, such as Richard Price and Joseph Priestly, also supported the American and French Revolutions.



Algernon Sidney was born in London in 1622. He was the son of nobility on both sides, and through his father was related to the famous poet and soldier Sir Philip Sidney. Sidney was raised in England but spent a portion of his later youth in Ireland, where his father was Lord Lieutenant. He served in the army for a time, and was elected to Parliament in 1646, during the period of conflict leading up to the civil war and Cromwell's Protectorate.

Sidney played a role in the trial of King Charles I, though he later acknowledged the trial to be illegitimate. He defended the execution of the king for most of his life, and moved in and out of politics. After the restoration of the monarchy in 1660, Sidney stayed in exile for a time, though he returned in 1677, became politically involved again, and was eventually executed for taking part in a plot against the life of King Charles II.

To read more about Algernon Sidney's life and works, please click here.


John Trenchard and Thomas Gordon were born in the mid 17th century. Both were English lawyers who practiced in London. They are known for having published together the political journal The Independent Whig. Later on, they also co-wrote 144 essays under the name "Cato", which are known as "Cato's Letters" and which were published in the London Journal. These essays became highly influential for the group known as the "Commonwealthmen." 

To read more about Trenchard and Gordon and their work, please click here.




a form of government in which the ruler has unlimited power and is not bound by a constitution or laws


the opposition to institutionalized religion and its intrusion into the daily life of citizens


the view that governments should function according to a fixed constitution

free trade:

trade that takes place without governmental interference


the part of a government that makes or changes laws

limited government:

the view that government should be involved as little as possible in the lives of its citizens

natural rights:

a collection of personal privileges or entitlements to act in a certain way such that others have a duty not to deny that entitlement. Natural rights pre-exist the establishment of government and are said to derive from nature, or constitution, of the human being.


a system of government in which citizens elect officials to represent them and to run the government on their behalf

social contract:

a contract or agreement in which people in their pre-political condition give up certain liberties and rights in order to enter into a political society. Social contract theory was highly influential in shaping the Constitution.


advocating socialism, the doctrine that the government should own industries

state of nature:

a real or imagined condition in which all human beings lived separately from one another before entering into government by means of a social contract



I. Introduction to the Radical Whigs: Several different groups could be called "Radical Whigs"

II. The First Wave of Radical Whigs: the original Whigs

A. opposed the centralized, absolute power of Charles II and the Stuart kings

B. One goal of the Whigs was to prevent the Catholic James, brother of Charles II, from becoming the king; some Whigs advocated this prevention by legal means, but others by violent action

C. Alergnon Sidney, who put forth a social contract theory similar to Locke's, was a first-wave Radical Whig who recommended violent plots

III. The Second Wave of Radical Whigs

A. With the Glorious Revolution, Whigs became more prominent in British politics; but many Whig followers became dissatisfied with current Whig leadership

B. Cato's Letters: a good example of second wave radical Whigs

1. Two second-wave Radical Whigs, John Trenchard and Thomas Gordon published Cato's Letters, a newspaper series opposing absolute government, and written by the fictional author "Cato"

2. Cato's Letters were popular in England and provided inspiration during the American Revolution

C. Second-wave Radical Whigs held views similar to Locke's social contract theory

1. Cato authors endorsed a state-of-nature view of human beings, in which people possess natural rights that are insecure

2. To amend this situation, people enter into society to secure their rights through government; thus government originates intentionally from the people

D. Cato's Letters and the practical implications of natural rights theory: Cato's Letters sought to draw out the practical implications of Locke's natural rights philosophy in the areas of religion, constitutionalism, and political economy

1. Outspokenly anti-clerical, Cato seized upon rights of conscience as inalienable and freedom of religion as the only just system

2. Like Locke, Cato advocates limited government and separation of powers, and condemns the informal ways in which this separation is overcome in society

3. Cato implies in many places that republican government may be the best system

4. In terms of property, Cato was in favor of free trade uninhibited by the state

IV. The Third Wave of Radical Whigs and the American Revolution

A. A second flowering of the Radical Whigs occured in the 1760s and 1770s when they sided with the American cause for independence

B. Richard Price wrote a defense of America and argued that civil liberty must be founded upon natural right

C. Price and his friend Joseph Priestly expanded on themes from Cato and Locke, developing a theory of federal government

D. Price, Priestly, and others also differed from Cato in being more concerned with religious issues, dissenting from the prevailing religious tradition in England at the time

V. French Revolution and the decline of the Radical Whigs

A. Radical Whigs in the late 18th century, such as Price, also supported the cause of the French Revolution

B. But after the powerful backlash that the French Revolution produced in England, a coherent Whig-identity collapsed

C. There were later Radicals, but they were more socialist and not as focused on natural rights



Part I.  Basic Interpretation of the Radical Whigs
If you are interested in the thought of the Radical Whigs after reading Zuckert’s essay, please go to the Primary Source Documents to read some of the essential passages from Cato’s Letters. Biographies of Algernon Sidney and Richard Price can be found here and here. As you go back to the primary sources, keep in mind the following questions:

  1. What were some of the central goals of the Radical Whigs?
  2. Why did Cato advocate a republican form of government?
  3. How did the Radical Whigs’ reaction against absolutism fuel their movement?
  4. What impact did social contract theory have on their political philosophy?
  5. How did the Radical Whigs view the American and French Revolutions?

Part II.  Connections to Other Thinkers
In order to understand the thought of the Radical Whigs more completely, it is important to place them in their proper contexts. Although influenced chiefly by the political events of the moment, their philosophy drew on the thought of John Locke and influenced, in turn, the political philosophy of the Americans of the Founding era. As you look deeper into the thought of the Radical Whigs, consider these questions in order to see how they fit into the broader history of ideas:

  1.  Cato says in his 24TH letter that “people, when they are not misled or corrupted, generally make a sound judgment of things…” This emphasis upon the common sense of the ordinary citizen is a theme that runs throughout the writings of the Radical Whigs, and ties into their rejection of absolutism. Contrast this position of common sense with Plato’s idea that only philosopher-kings should rule a state, because they are the wisest and most knowledgeable.
  2. In their political philosophies, Hobbes and the Radical Whigs start from quite similar premises. Both see people as originally non-political, existing in a state of nature, possessing natural rights, and entering into society by contract in order to secure those rights. However, while Hobbes and the Radical Whigs share these similar premises, they differ radically in their conclusions: Hobbes advocates an absolute monarchy, and the Radical Whigs are opposed to absolutism in all forms. What accounts for these quite different conclusions?
  3. In his Second Treatise of Government, Locke argues that slavery is permissible as a form of delayed punishment for those who have forfeited their lives. At the same time, however, while Locke deeply influenced the theories of the Radical Whigs, Cato writes in his 62nd letter that slavery is “a continual state of uncertainty and wretchedness” and that even those who rule over slaves are themselves slavish. Why is there such a great difference between Cato and Locke on this point? Are there deeper philosophical differences between the two writers?
  4. In his 40th letter, Cato writes, “We do not expect philosophical virtue from [men]; but only that they follow virtue as their interest, and find it penal and dangerous to depart from it.” Here, Cato says that the only virtue that the law should produce in men is that they obey the laws so as not to be punished. Compare this with Aquinas’ notion that the law should make men virtuous. How similar are these two positions? How different are they? Is Cato following Thomas Aquinas in this passage?
  5. Many of the Radical Whigs held strongly anti-clerical views, and thought that religious institutions should not interfere with the lives of ordinary citizens.  How does this compare with John Rawls’ position that people should not take their religious beliefs into account when considering political matters?

Part III.  Critical Interpretations of the Radical Whigs
With a basic understanding of the theories of the Radical Whigs, let us examine their work more critically. Are their arguments persuasive? Can we expand their theories to determine what they would say about issues that they did not directly address? Use the questions below as your guide:

  1.  According to Cato in his 60th letter, a government  “can have no power, but such as men can give, and such as they actually did give, or permit for their own sake.” While this passage certainly reinforces the Lockean notion that government is legitimated only by the consent of the governed, Cato seems to be wavering between explicit and implicit consent. Does Cato think that the citizens of a government need to give explicit, conscious consent to the government, or is a government legitimate even when its citizens have only given their implicit, unconscious consent?
  2. A criticism that one might make of any social contract theory is that it presupposes an original state of nature that may never have existed. If this state of nature never existed, one might say, the whole social contract theory is invalidated—because that is not in fact how governments are formed. Is this a valid criticism? If it is true, does the criticism undermine the Radical Whigs’ social contract theory? Does it matter if an original state of nature never existed, or an initial social contract never took place?
  3. The Radical Whigs valued liberty and free trade quite highly and fundamentally. At first glance, this seems logical, for if one truly has liberty, then one should be at liberty to trade freely. But yet, in the long run, it would seem that the two notions contradict one another. For example, it is reasonably conceivable that someone with enough money could achieve a monopoly in a certain industry or win an election because of superior funds, and thereby significantly limit the liberty of others. With this in mind, how can the Radical Whigs advocate both liberty and free trade? How could they harmonize these two ideals?
  4. In addition to legal measures, the Radical Whigs also promoted violent action, both within England and in foreign movements such as the French and American Revolution. This advocacy of violent action connects with their social contract position that citizens can legitimately overthrow the government if it ceases to secure and protect their rights. But to what extent is violent action justified? Is there a sense in which some revolutions or plots are justified, while others are not?
  5. It is often said that rights imply duties. If someone has the right to free speech, for instance, that person therefore has a duty to respecting others’ rights to free speech. But while the Radical Whigs, writing in Locke’s tradition, focus upon the role of natural rights in society, they say very little about the duties of citizens in society. To what extent do you think that rights imply duties? What would the Radical Whigs say about the duties of citizens?

Part IV.  Contemporary Connections
The Radical Whigs were struggling with questions about liberty, the role of government, the proper attitude toward trade, the legitimate province of religion, among other things. These are perennial questions that continue to occupy us today. Therefore, let us now turn to some contemporary issues and see how the thought of the Radical Whigs might be applied to them:

  1. As Zuckert notes, Cato condemns the various “informal devices by which the formal separation of powers within institutions of the constitution was overcome.” What are some of these “informal devices” in contemporary American society? How do people today criticize some of these “devices”? Are their criticisms similar to those of Cato and the Radical Whigs?
  2. People in modern society tend to define freedom as being able to do whatever one wants, free of obligations and outside influences. In other words, for the modern world, freedom is freedom from constraint. But, given that liberty is something they value highly, how would the Radical Whigs view this definition of freedom? Do they hold a view of freedom similar to contemporary society’s definition, or do they provide a different account? For the Radical Whigs, is freedom merely the ability and right to do whatever one wants?
  3. There is a strong moral sentiment in contemporary American society that one should try, as much as possible, to help and send aid to impoverished and war-torn countries around the world. The many organizations providing hunger relief and AIDS treatment in Africa, for instance, serve as examples of this moral sentiment. However, this vision of helping the world at large stands in contrast to Richard Price’s position in his “Discourse on the Love of Our Country.” There, he argues that each person “is charged primarily with the care of himself. Next come our families, and benefactors, and friends; and after them, our country. We can do little for mankind at large.” In other words, for Price, the duty to self, family, friends, and country takes precedence over the duty to the world at large. What, then, would Price think of this modern impulse to help mankind? Would he think that we should put to domestic use the funds and supplies that we send overseas? Or do you think his statement that “[we] can do little for mankind at large” no longer applies in our mobile, technological society in which we can send aid across the globe with relative ease?
  4. Today, Western society seems to emphasize increasingly the tolerance of different religious groups and the intolerance of any religion that attempts to have public precedence over other religions. One can, for example, see this emphasis reflected in the secularization of national holidays such as Christmas and Easter. In what ways is this removal of religion from the public sphere similar to the anti-clericalism of Locke and, more vocally, of Cato? What would the Radical Whigs think about these contemporary views towards religion in public and political life?