Whenever this suggestion arises, my mind instantly turns to a passage from Edward Gibbon's 1776 opus The History of the Decline and Fall of the Roman Empire (paragraph breaks mine):
The division of Europe into a number of independent states, connected, however, with each other, by the general resemblance of religion, language, and manners, is productive of the most beneficial consequences to the liberty of mankind.
A modern tyrant, who should find no resistance either in his own breast or in his people, would soon experience a gentle restraint from the example of his equals, the dread of present censure, the advice of his allies, and the apprehension of his enemies.
The object of his displeasure, escaping from the narrow limits of his dominions, would easily obtain, in a happier climate, a secure refuge, a new fortune adequate to his merit, the freedom of complaint, and perhaps the means of revenge. But the empire of the Romans filled the world, and, when that empire fell into the hands of a single person, the world became a safe and dreary prison for his enemies.
The slave of Imperial despotism, whether he was condemned to drag his gilded chain in Rome and the senate, or to wear out a life of exile on the barren rock of Seriphus, or the frozen banks of the Danube, expected his fate in silent despair. To resist was fatal, and it was impossible to fly.
On every side he was encompassed with a vast extent of sea and land, which he could never hope to traverse without being discovered, seized, and restored to his irritated master.
Beyond the frontiers, his anxious view could discover nothing, except the ocean, inhospitable deserts, hostile tribes of barbarians, of fierce manners and unknown language, or dependent kings, who would gladly purchase the emperor’s protection by the sacrifice of an obnoxious fugitive.
“Wherever you are,” said Cicero to the exiled Marcellus, “remember that you are equally within the power of the conqueror.”