Niccolò Machiavelli
Discourses on the First Decade of Titus Livius (Chap. 3.24)
That prolonged Commands brought Rome to Servitude.

If we well examine the course of Roman history, we shall find two causes leading to the break-up of that republic: one, the dissensions which arose in connection with the agrarian laws; the other, the prolongation of commands. For had these matters been rightly understood from the first, and due remedies applied, the freedom of Rome had been far more lasting, and, possibly, less disturbed. And although, as touching the prolongation of commands, we never find any tumult breaking out in Rome on that account, we do in fact discern how much harm was done to the city by the ascendency which certain of its citizens thereby gained. This mischief indeed would not have arisen, if other citizens whose period of office was extended had been as good and wise as Lucius Quintius, whose virtue affords a notable example. For terms of accord having been settled between the senate and commons of Rome, the latter, thinking their tribunes well able to withstand the ambition of the nobles, prolonged their authority for a year. Whereupon, the senate, not to be outdone by the commons, proposed, out of rivalry, to extend the consulship of Quintius. He, however, refused absolutely to lend himself to their designs, and insisted on their appointing new consuls, telling them that they should seek to discredit evil examples, not add to them by setting worse. Had this prudence and virtue of his been shared by all the citizens of Rome, the practice of prolonging the terms of civil offices would not have been suffered to establish itself, nor have led to the kindred practice of extending the term of military commands, which in progress of time effected the ruin of their republic.

The first military commander whose term was extended, was Publius Philo; for when his consulship was about to expire, he being then engaged in the siege of Palæopolis, the senate, seeing he had the victory in his hands, would not displace him by a successor, but appointed him Proconsul, which office he was the first to hold. Now, although in thus acting the senate did what they thought best for the public good, nevertheless it was this act of theirs that in time brought Rome to slavery. For the further the Romans carried their arms, the more necessary it seemed to them to grant similar extensions of command, and the oftener they, in fact, did so. This gave rise to two disadvantages: first that a smaller number of men were trained to command; second, that by the long continuance of his command a captain gained so much influence and ascendency over his soldiers that in time they came to hold the senate of no account, and looked only to him. This it was, that enabled Sylla and Marius to find adherents ready to follow them even to the public detriment, and enabled Cæsar to overthrow the liberties of his country; whereas, had the Romans never prolonged the period of authority, whether civil or military, though they might have taken longer to build up their empire, they certainly had been later in incurring servitude.