“Political realism believes that politics, like society in general, is governed by objective laws that have their roots in human nature.”

Principles and Priorities : Programme for Government (September 5, 2007)

"On Parties" (23 January 1792), Papers of James Madison Vol. XIV, pp. 197-8 http://press-pubs.uchicago.edu/founders/documents/v1ch15s50.html
Mr. Madison wished to relieve the sufferers, but was afraid of establishing a dangerous precedent, which might hereafter be perverted to the countenance of purposes very different from those of charity. He acknowledged, for his own part, that he could not undertake to lay his finger on that article in the Federal Constitution which granted a right of Congress of expending, on objects of benevolence, the money of their constituents.
Summation of Madison's remarks (10 January 1794) Annals of Congress, House of Representatives, 3rd Congress, 1st Session, p. 170 http://memory.loc.gov/cgi-bin/ampage?collId=llac&fileName=004/llac004.db&recNum=82; the expense in question was for French refugees from the Haitian Revolution; this summation has been paraphrased as if a direct quote: "I cannot undertake to lay my finger on that article of the Constitution which granted a right to Congress of expending, on objects of benevolence, the money of their constituents."
1790s
Context: In every political society, parties are unavoidable. A difference of interests, real or supposed, is the most natural and fruitful source of them. The great object should be to combat the evil: 1. By establishing a political equality among all. 2. By withholding unnecessary opportunities from a few, to increase the inequality of property, by an immoderate, and especially an unmerited, accumulation of riches. 3. By the silent operation of laws, which, without violating the rights of property, reduce extreme wealth towards a state of mediocrity, and raise extreme indigence towards a state of comfort. 4. By abstaining from measures which operate differently on different interests, and particularly such as favor one interest at the expence of another. 5. By making one party a check on the other, so far as the existence of parties cannot be prevented, nor their views accommodated. If this is not the language of reason, it is that of republicanism.

There are no authorities which are not overseen, within nonlinear structures. Constitutional language is formally constructed to eliminate all ambiguity and to be processed algorithmically. Democratic elements, along with official discretion, and legal judgment, is incorporated reluctantly, minimized in principle, and gradually eliminated through incremental formal improvement. Argument defers to mathematical expertise. Politics is a disease that the constitution is designed to cure.
"A Republic, If You Can Keep It" https://web.archive.org/web/20140327090001/http://www.thatsmags.com/shanghai/articles/12321 (2013) (original emphasis)

The Rights of Man (1945). London: Geoffrey Bles, pp. 7–8.

On gender equality: United States v. Virginia (1996) (dissenting).
1990s

Our Revolutionary Right, 1999.
1990s, 1990

Six Principles of Political Realism, § 4.
Politics Among Nations (1948)
Context: Political realism is aware of the moral significance of political action. It is also aware of the ineluctable tension between the moral command and the requirements of successful political action. And it is unwilling to gloss over and obliterate that tension and thus to obfuscate both the moral and the political issue by making it appear as though the stark facts of politics were morally more satisfying than they actually are, and the moral law less exacting than it actually is.

Source: 1850s, An Investigation of the Laws of Thought (1854), p. 4; Ch. 1. Nature And Design Of This Work
Context: The general laws of Nature are not, for the most part, immediate objects of perception. They are either inductive inferences from a large body of facts, the common truth in which they express, or, in their origin at least, physical hypotheses of a causal nature serving to explain phenomena with undeviating precision, and to enable us to predict new combinations of them. They are in all cases, and in the strictest sense of the term, probable conclusions, approaching, indeed, ever and ever nearer to certainty, as they receive more and more of the confirmation of experience. But of the character of probability, in the strict and proper sense of that term, they are never wholly divested. On the other hand, the knowledge of the laws of the mind does not require as its basis any extensive collection of observations. The general truth is seen in the particular instance, and it is not confirmed by the repetition of instances.

The Paris Review interview (1958)
Context: I'm an American, and always will be. I happen to love that big, awkward, sprawling country very much — and its big, awkward, sprawling people. Anyway, I don't like politics; and I don't make "political gestures," as you call it. I don't even believe in politics. To me, politics is like one of those annoying, and potentially dangerous (but generally just painful) chronic diseases that you just have to put up with in your life if you happen to have contracted it. Politics is like having diabetes. It's a science, a catch-as-catch-can science, which has grown up out of simple animal necessity more than anything else. If I were twice as big as I am, and twice as physically strong, I think I'd be a total anarchist. As it is, since I'm physically a pretty little guy... no, in fact, one reason I left was because I believe it is good for an American writer to get outside his country — outside his continent — and see it from a vantage point outside its pervading emotional climate.