Niccolò Machiavelli
Discourses on the First Decade of Titus Livius (Chap. 1.35)
Why the Creation of the Decemvirate in Rome, although brought about by the free and open Suffrage of the Citizens, was hurtful to the Liberties of that Republic

The fact of those ten citizens who were chosen by the Roman people to make laws for Rome, in time becoming her tyrants and depriving her of her freedom, may seem contrary to what I have said above, namely that it is the authority which is violently usurped, and not that conferred by the free suffrages of the people which is injurious to a republic. Here, however, we have to take into account both the mode in which, and the term for which authority is given. Where authority is unrestricted and is conferred for a long term, meaning by that for a year or more, it is always attended with danger, and its results will be good or bad according as the men are good or bad to whom it is committed. Now when we compare the authority of the Ten with that possessed by the dictator, we see that the power placed in the hands of the former was out of all proportion greater than that entrusted to the latter. For when a dictator was appointed there still remained the tribunes, the consuls, and the senate, all of them invested with authority of which the dictator could not deprive them. For even if he could have taken his consulship from one man, or his status as a senator from another, he could not abolish the senatorial rank nor pass new laws. So that the senate, the consuls, and the tribunes continuing to exist with undiminished authority were a check upon him and kept him in the right road. But on the creation of the Ten, the opposite of all this took place. For on their appointment, consuls and tribunes were swept away, and express powers were given to the new magistrates to make laws and do whatever else they thought fit, with the entire authority of the whole Roman people. So that finding themselves alone without consuls or tribunes to control them, and with no appeal against them to the people, and thus there being none to keep a watch upon them, and further being stimulated by the ambition of Appius, in the second year of their office they began to wax insolent.

Let it be noted, therefore, that when it is said that authority given by the public vote is never hurtful to any commonwealth, it is assumed that the people will never be led to confer that authority without due limitations, or for other than a reasonable term. Should they, however either from being deceived or otherwise blinded, be induced to bestow authority imprudently, as the Romans bestowed it on the Ten, it will always fare with them as with the Romans. And this may readily be understood on reflecting what causes operated to keep the dictator good, what to make the Ten bad, and by observing how those republics which have been accounted well governed, have acted when conferring authority for an extended period, as the Spartans on their kings and the Venetians on their doges; for it will be seen that in both these instances the authority was controlled by checks which made it impossible for it to be abused. But where an uncontrolled authority is given, no security is afforded by the circumstance that the body of the people is not corrupted; for in the briefest possible time absolute authority will make a people corrupt, and obtain for itself friends and partisans. Nor will it be any hindrance to him in whom such authority is vested, that he is poor and without connections, for wealth and every other advantage will quickly follow, as shall be shown more fully when we discuss the appointment of the Ten.