Book I, Chapter VI, part 2
Whether it was possible to establish in Rome a government capable of putting an end to the enmities existing between the nobles and the people.
In examining now all these circumstances, we see that the legislators of Rome had to do one of two things to assure to their republic the same quiet as that enjoyed by the two republics of which we have spoken; namely, either not to employ the people in the armies, like the Venetians, or not to open the doors to strangers, as had been the case in Sparta. But the Romans in both took just the opposite course, which gave to the people greater power and infinite occasion for disturbances. But if the republic had been more tranquil, it would necessarily have resulted that she would have been more feeble, and that she would have lost with her energy also the ability of achieving that high degree of greatness to which she attained; so that to have removed the cause of trouble from Rome would have been to deprive her of her power of expansion. And thus it is seen in all human affairs, upon careful examination, that you cannot avoid one inconvenience without incurring another. If therefore you wish to make a people numerous and warlike, so as to create a great empire, you will have to constitute it in such manner as will cause you more difficulty in managing it; and if you keep it either small or unarmed, and you acquire other dominions, you will not be able to hold them, or you will become so feeble that you will fall a prey to whoever attacks you. And therefore in all our decisions we must consider well what presents the least inconveniences, and then choose the best, for we shall never find any course entirely free from objections. Rome then might, like Sparta, have created a king for life, and established a limited senate; but with her desire to become a great empire, she could not, like Sparta, limit the number of her citizens; and therefore a king for life and a limited senate would have been of no benefit to her so far as union was concerned. If any one therefore wishes to establish an entirely new republic, he will have to consider whether he wishes to have her expand in power and dominion like Rome, or whether he intends to confine her within narrow limits. In the first case, it will be necessary to organize her as Rome was, and submit to dissensions and troubles as best he may; for without a great number of men, and these well armed, no republic can ever increase. In the second case, he may organize her like Sparta and Venice; but as expansion is the poison of such republics, he must by every means in his power prevent her from making conquests, for such acquisitions by a feeble republic always prove their ruin, as happened to both Sparta and Venice; the first of which, having subjected to her rule nearly all Greece, exposed its feeble foundations at the slightest accident, for when the rebellion of Thebes occurred, which was led by Pelopidas, the other cities of Greece also rose up and almost ruined Sparta.
In like manner, Venice, having obtained possession of a great part of Italy, and the most of it not by war, but by means of money and fraud, when occasion came for her to give proof of her strength, she lost everything in a single battle. I think, then, that to found a republic which should endure a long time it would be best to organize her internally like Sparta, or to locate her, like Venice, in some strong place; and to make her sufficiently powerful, so that no one could hope to overcome her readily, and yet on the other hand not so powerful as to make her formidable to her neighbors. In this wise she might long enjoy her independence. For there are but two motives for making war against a republic: one, the desire to subjugate her; the other, the apprehension of being subjugated by her. The two means which we have indicated remove, as it were, both these pretexts for war; for if the republic is difficult to be conquered, her defences being well organized, as I presuppose, then it will seldom or never happen that any one will venture upon the project of conquering her. If she remains quiet within her limits, and experience shows that she entertains no ambitious projects, the fear of her power will never prompt any one to attack her; and this would even be more certainly the case if her constitution and laws prohibited all aggrandizement. And I certainly think that if she could be kept in this equilibrium it would be the best political existence, and would insure to any state real tranquillity. But as all human things are kept in a perpetual movement, and can never remain stable, states naturally either rise or decline, and necessity compels them to many acts to which reason will not influence them; so that, having organized a republic competent to maintain herself without expanding, still, if forced by necessity to extend her territory, in such case we shall see her foundations give way and herself quickly brought to ruin. And thus, on the other hand, if Heaven favors her so as never to be involved in war, the continued tranquillity would enervate her, or provoke internal dissensions, which together, or either of them separately, will be apt to prove her ruin. Seeing then the impossibility of establishing in this respect a perfect equilibrium, and that a precise middle course cannot be maintained, it is proper in the organization of a republic to select the most honorable course, and to constitute her so that, even if necessity should oblige her to expand, she may yet be able to preserve her acquisitions. To return now to our first argument, I believe it therefore necessary rather to take the constitution of Rome as a model than that of any other republic, (for I do not believe that a middle course between the two can be found,) and to tolerate the differences that will arise between the Senate and the people as an unavoidable inconvenience in achieving greatness like that of Rome. Besides the other reasons alleged, which demonstrate the creation and authority of the Tribunes to have been necessary for the protection of liberty, it is easy to see the advantage which a republic must derive from the faculty of accusing, which amongst others was bestowed upon the Tribunes, as will be seen in the following chapter.
Switzerland took the "be too tough to conquer, never expand" route, and it worked well for them. Their landlocked mountains were a tough place to live, and helped prevent the enervation Machiavelli worried about, and their mercenary ventures no doubt did much more to prevent decay.