Okay, I'll bite. What WAS the "then assumed maximum size of a representative republic"?
As far as I know, none of them strickly defined a size in the way that Aristotle did in regard to a polis, which one author indicated was somewhere in the vicinity of of 40 square miles and containing 500 to 1000 households – which is obviously quite small. Technology in communication and division of labor in economics makes a difference since average household in such a polis would be about 30 acres, which in Aristotle’s assumption of economic autarchy would supply
“sufficient wine, oil, grain, legumes, fruit, milk for daily living, and meat on occasion…”
But, his main criterion was that
“the citizens should know each other and know what kind of people they are.” Unless citizens can know one another sufficiently well, they won’t know whom to trust (and in particular who can be trusted to hold official positions) and the leaders won’t be able to understand the people they lead well enough to do so well. When he noted that the large cities of his day had been shown to be governed haphazardly and poorly, he was talking about their size as an increase above an upper range. He was basically contending that large size led to social fracturing that undermined a polis.
Machiavelli considered the limit as twelve or fourteen communities, after which either “
confusion” grows or some of them are made
“subjects.” He also discussed the idea of cultural coherence and
“for bidding extension, and looking only to defence, and taking heed that their defences are in good order, as do those republics of Germany which live and for long have lived, in freedom.” Of course, that was before Napoleon ripped through Germany and helped trigger a Prussian response that went in very unfortunate directions.
Machiavelli saw the dilemma this way:
“
...when we have given institutions to a State on the footing that it is to maintain itself without enlargement, should necessity require its enlargement, its foundations will be cut from below it, and its downfall quickly ensue. On the other hand, were a republic so favoured by Heaven as to lie under no necessity of making war, the result of this ease would be to make it effeminate and divided which two evils together, and each by itself, would insure its ruin.”
Montesquieu, whom everyone studied back then, said popular governments are driven by the principle of virtue. That republics could only exist in a small territory because in large republics there emerges opportunities for great wealth, and individuals are more likely to sacrifice the common good in order to pursue individual goals – one can achieve greatness
“only on the ruins of his homeland.”
The outlook of both Machiavelli and Montesquieu looms large in Madison’s
Federalist writings – both the question of expansion
(Federalist No. 14) and uneven wealth distribution as the source of what he called
“factions” in
Federalist No. 10 – and both concerns scream at us today. Indeed,
“factions” arrived almost immediately in the wake of Alexander Hamilton’s economic policies, which set the stage for the expansion that Machiavelli and Montesquieu had warned about even as wealth inequalities that worried him in
Federalist No. 10 began to appear.
That rapidly got to the point where Madison, just a decade removed from his
Federalist writings, repudiated much of his centralizing ways and shockingly abandoned the Federalists to become a fellow traveler with Jefferson, whose vision of political decentralization and local control has some parallel with Aristotle’s polis – a large number of smaller, decentralized American political units with only minimal authority and power granted to a central state.
Without an understanding of what Federalist rule meant immediately, Madison reversals looks like naked political expediency – a reed blowing in the wind – and that, I believe is unfair to him.
New York Governor George ....... was on of the anti-Federalists who raised the concern
“
...whoever seriously considers the immense extent of territory comprehended within the limits of the United States, together with the variety of its climates, productions, and commerce, the difference of extent, and number of inhabitants in all; the dissimilitude of interest, morals, and politics, in almost every one, will receive it as an intuitive truth, that a consolidated republican form of government therein, can never form a perfect union, establish justice, insure domestic tranquility, promote the general welfare, and secure the blessings of liberty to you and your posterity, for to these objects it must be directed. This unkindred legislature therefore, composed of interests opposite and dissimilar in their nature, will in its exercise, emphatically be like a house divided against itself…
In large republics, the public good is sacrificed to a thousand views, in a small one, the interest of the public is easily perceived, better understood, and more within the reach of every citizen; abuses have a less extent, and of course are less protected. He also shows you, that the duration of the republic of Sparta was owing to its having continued with the same extent of territory after all its wars; and that the ambition of Athens and Lacedemon to command and direct the union, lost them their liberties, and gave them a monarchy.”
Consolidation was a great fear in the wake of the experience with England and the historical evidence was so one-sided in its examples that in
Federalist No. 70 (on executive power), Hamilton, who consistently disdained mere speculation and quoted his preferred history as strong evidence, was driven to
“quitting the dim light of historical research, attaching ourselves purely to the dictates of reason and good sense.”
Bernard Bailyn in his
The Ideological Origins of the American Revolution (Pulitzer Prize and the Bancroft Prize) went back to Charles Inglis’ 1776 pamphlet,
The True Interest of America: Strictures on a Pamphlet Intitled Common Sense and Jonathan Boucher’s
A View of the Causes and Consequences of the American Revolution 1797) to note that:
“
Republics had always been known to be delicate polities, peculiarly susceptible to inner convulsions and outer pressures. And the larger the state the greater the danger. Monarchy, it was generally agreed, was best suited to extensive domains, popular government to small territories. The great and glorious republics of the past—‘the ancient republics—Rome, Carthage, Athens, etc.,’ and more recently Switzerland and Holland—had all been small in size compared with the united colonies, compared even with most of the individual states. Republican government ‘may do well enough for a single city or small territory, but would be utterly improper for such a continent as this. America is too unwieldy for the feeble, dilatory administration of democracy.’"
So, there is no hard, fast answer to your question. But, whatever flaws that can be found in the argumentation of the anti-Federalists (who were really the Federalists who lost the word definition struggle, if you think about it), I think it can be asserted that Aristotle, Machiavelli, Montesquieu, and the anti-Federalists in general have stood the test of American time better than Madison, Hamilton, and the other theorists who found it necessary to deny them in regard to the size of a republic.
