… is from James Madison’s April 1787 memo, “Vices of the Political System of the United States ,” which I first discovered long ago when reading William Lee Miller’s 1992 book, The Business of May Next: James Madison & the Founding :
Representative appointments are sought from 3 motives. 1. ambition 2. personal interest. 3. public good. Unhappily the two first are proved by experience to be most prevalent. Hence the candidates who feel them, particularly, the second, are most industrious, and most successful in pursuing their object: and forming often a majority in the legislative Councils, with interested views, contrary to the interest, and views, of their Constituents, join in a perfidious sacrifice of the latter to the former. A succeeding election it might be supposed, would displace the offenders, and repair the mischief. But how easily are base and selfish measures, masked by pretexts of public good and apparent expediency? How frequently will a repetition of the same arts and industry which succeeded in the first instance, again prevail on the unwary to misplace their confidence?
How frequently too will the honest but unenlightened representative be the dupe of a favorite leader, veiling his selfish views under the professions of public good, and varnishing his sophistical arguments with the glowing colours of popular eloquence?
Jim Buchanan  often said that his and Gordon Tullock ‘s work in public-choice  and constitutional economics is, at bottom, little more than an elaboration upon, and a modernizing of, the political realism of America’s founders, especially that of James Madison.
One of the flaws of the modern punditry – and, more generally, of what Deirdre McCloskey  calls “the herd of independent minds” – that I find most distressing is its refusal to be cured of its cancerous romanticism about government and coerced collective actions. Faith that some Great Man or Great Woman or Great Council – faith that some secular savior or saviors – can be found or fashioned to exercise power selflessly and in ways that, We are promised, will improve upon the realities of free markets and other venues of voluntary human interactions is an unshakable conviction among far too many elite pundits and intellectuals (who, amazingly, fancy themselves to be reality-based and science-driven).