A discussion of what constituted the "guard of freedom" in the Roman Republic takes place at the end of Chapter Four and throughout Chapter Five. But what, exactly, does it mean to be the "guard of freedom?" What qualities does such a guard possess?
Machiavelli never precisely defines what the term means. Hints appear in the text, of course. Machiavelli says explicitly that the tribunes were a guard of freedom in early Rome. And he asserts that the longevity of a "free way of life" in a state directly corresponds to how well the guard of freedom has been placed in the proper institution.
So it seems reasonable to reach two initial conclusions: (1) some function or functions of the Roman tribunes are those of a guard of freedom generally, and (2) the guard of freedom does not necessarily create freedom rather than simply preserving what freedom already exists.
Machiavelli provides another clue in the middle of Chapter Five, however, when he refers to the guard of freedom as a "stick" through which powerful people can satisfy their ambition. The guard thus appears to have some sort of offensive function -- a power to elevate oneself at the expense of others -- instead of a purely defensive tool to keep one from being offended.
Where would one find such a "stick" in the Roman tribunes, then? As I understand it, among their most important powers were the authority to (1) veto measures proposed by the Senate, (2) convoke and preside over the Plebeian Council, and (3) arrest, try, and pass judgment upon those who offended the rights of the plebeians through that Council.
Of these, the last power appears to be the most closely associated with Machiavelli's idea of freedom. The veto, while powerful, was hardly unique to the tribune, given that either consul also held identical or similar authority. The power to convoke and lead the Council as a popular legislative body also carries great political weight, but that legislative function does not seem particularly germane to the tribunes' role as a guard of freedom given that Machiavelli deemed that the nobility could hold the guard of freedom as well, such as in Venice and Sparta.
Rather, the tribunes' judicial role strikes me as the heart of their ability to preserve liberty. I say this based on Machiavelli's comments, scattered throughout the Discourses and The Prince, indicating the critical role that judicial power plays in suppressing the rule of one alone. Book One, Chapter Seven, for example, states that those charged with the guard of freedom
cannot give a more useful and necessary authority than that of being able to accuse citizens to the state, or to some magistrate or counsel, when thy sin in anything against the free state.This is essentially a judicial function, for the ability to accuse is inextricably entwined with the power to judge and to condemn. Moreover, the details of that chapter leave little doubt that Machiavelli included what moderns would recognize as the judicial power in the power to accuse. For he references the legendary case of Coriolanus, whom the tribunes called before the people to receive their judgment for alleged wrongs, as told by Shakespeare:
Sicinius [a tribune]: Draw near, ye people.
Aedile: List to your tribunes. Audience ! peace, I say !
Coriolanus: First, hear me speak.
Both Tribunes: Well, say. Peace, ho !
Coriolanus: Shall I be charged no further than this present?
Must all determine here?
Sicinius: I do demand,
If you submit you to the people's voices,
Allow their officers and are content
To suffer lawful censure for such faults
As shall be proved upon you?
Coriolanus: I am content.
A few paragraphs later, Machiavelli again ties the power to accuse with the power to judge, noting that in Florence "there was no mode of accusation against the ambition of powerful citizens" because there were not enough judges in that state. Half a book later, in paragraph three of Book One, Chapter Forty, Machiavelli again links the importance of the tribunes to their judicial power when he states that the Roman people initially agreed to the tyrannical rule of the decemvirate in part because the decemvirs had given to them the power to judge cases. Thus, he asserts, the people no longer felt the need for tribunes, who usually held such authority. The reader is left to conclude that the Roman plebs considered this judicial power a key component of their freedom.
Further, the importance of judicial power to the freedom of a state does not confine itself to instances where the people exercise the guard of freedom. In Venice, Machiavelli claims in Book One, Chapter Forty-nine, the powerful were held in check by the powerful themselves -- or, more specifically, by the powerful who exercised the judicial function. In the Venetian example, this judicial authority stemmed from a council of "ten citizens who could punish any citizen without appeal.[.]" Although the council delegated this power to a larger body, the root of that power, and thus the root of the Venetians' guard of freedom, came from the great citizens of that state.
Two excerpts from The Prince strongly buttress this conclusion. The first and most conspicuous of the two lies in the notorious last paragraph of Chapter XVIII, where Machiavelli writes that "in the actions of all men ... one looks to the end" and not to the means. This statement, breathtakingly bold and impious, receives one -- and only one -- caveat. "[O]ne looks to the end" when considering the actions of a prince, Machiavelli states, but only "where there is no court to appeal to ....." Any mention of a legislature, senate, or council of commoners exercising such power remains conspicuously absent. Only the judicial authority is cited as an ultimate brake on absolute princely power.
The second excerpt is found in Chapter IX. At the end of the chapter, Machiavelli discourses on the ability of a prince in a "civil principality" -- i.e. a principality ordered by some form of law -- "to ascend ... to an absolute one" -- i.e. a principality where the prince exercises power to the exclusion of all other sources, including the law. Such a power grab becomes more difficult, he says, when the prince has ruled "by means of magistrates," which should include judges, rather than through his own person. In that instance, the citizens "are accustomed to receive commands from the magistrates" (e.g., judges) and are thus less likely to obey the extralegal commands of the prince. Again, the judicial power restricts the prince's ability to overthrow the rule of law.
Taken together, these passages at the very least create the impression that Machiavelli saw the "guard of freedom" as resting to a large degree on the suppression of the excess ambitions of the powerful, and that he thought this purpose best accomplished through the exercise of judicial power. So it stands to reason that Machiavelli understood the judiciary to play a preeminent role in safeguarding republican liberty. Thus, it links Machiavelli to Chief Justice John Marshall, who centuries later cemented the American judiciary's role as ultimate arbiter of our country's rule of law through the concept of judicial review.