Montesquieu, "The Spirit of the Laws"
It is natural for a republic to have only a small territory; otherwise it cannot long subsist. In an extensive republic there are men of large fortunes, and consequently of less moderation; there are trusts too considerable to be placed in any single subject; he has interests of his own; he soon begins to think that he may be happy and glorious by oppressing his fellow-citizens; and that he may raise himself to grandeur on the ruins of his country.
In an extensive republic the public good is sacrificed to a thousand private views; it is subordinate to exceptions, and depends on accidents. In a small one the interest of the public is more obvious, better understood, and more within the reach of every citizen; abuses have less extent, and, of course, are less protected.
A monarchical state ought to be of moderate extent. Were it small, it would form itself into a republic; were it very large, the nobility, possessed of great estates, far from the eye of the prince, with a private court of their own, and secure, moreover, from sudden executions by the laws and manners of the country—such a nobility, I say, might throw off their allegiance, having nothing to fear from too slow and too distant a government.
A large empire supposes a despotic authority in the person who governs. It is necessary that the quickness of the prince's resolutions should supply the distance of the places they are sent to; that fear should prevent the remissness of the distant governor or magistrate; that the law should be derived from a single person, and should shift continually, according to the accidents which necessarily multiply in a state in proportion to its extent.
A NEW PHYSICAL CAUSE OF THE SLAVERY OF ASIA, AND OF THE LIBERTY OF EUROPE
In Asia they have always had great Empires; in Europe these could never subsist. Asia has larger plains; it is cut out into much more extensive divisions by mountains and seas; and as it lies more to the south, its springs are more easily dried up; the mountains are less covered with snow; and the rivers being not so large, form more contracted barriers.
Power in Asia ought then to be always despotic; for if their slavery was not severe they would soon make a division inconsistent with the nature of the country.
In Europe the natural division forms many nations of a moderate extent, in which the ruling by laws is not incompatible with the maintenance of the state; on the contrary, it is so favorable to it, that without this the state would fall into decay, and become a prey to its neighbors.
It is this which has formed a genius for liberty that renders every part extremely difficult to be subdued and subjected to a foreign power, otherwise than by the laws and the advantage of commerce.
On the contrary, there reigns in Asia a servile spirit, which they have never been able to shake off, and it is impossible to find in all the histories of that country a single passage that discovers a freedom of spirit; we shall never see anything there but the excess of slavery.