Alexander Hamilton, John Jay, and James Madison, The Federalist (Gideon ed.). (Indianapolis: Liberty Fund, 1818). https://teachingamericanhistory.org/lgkg

Federalist 47 | February 1, 1788

To the People of the State of New York:

Having reviewed the general form of the proposed government and the general mass of power allotted to it, I proceed to examine the particular structure of this government, and the distribution of this mass of power among its constituent parts.

One of the principal objections inculcated by the more respectable adversaries to the Constitution is its supposed violation of the political maxim that the legislative, executive, and judiciary departments ought to be separate and distinct. In the structure of the federal government, no regard, it is said, seems to have been paid to this essential precaution in favor of liberty. The several departments of power are distributed and blended in such a manner as at once to destroy all symmetry and beauty of form, and to expose some of the essential parts of the edifice to the danger of being crushed by the disproportionate weight of other parts.

No political truth is certainly of greater intrinsic value, or is stamped with the authority of more enlightened patrons of liberty, than that on which the objection is founded. The accumulation of all powers, legislative, executive, and judiciary, in the same hands, whether of one, a few, or many, and whether hereditary, self-appointed, or elective, may justly be pronounced the very definition of tyranny. Were the federal Constitution, therefore, really chargeable with the accumulation of power, or with a mixture of powers, having a dangerous tendency to such an accumulation, no further arguments would be necessary to inspire a universal reprobation of the system. I persuade myself, however, that it will be made apparent to everyone, that the charge cannot be supported, and that the maxim on which it relies has been totally misconceived and misapplied. In order to form correct ideas on this important subject, it will be proper to investigate the sense in which the preservation of liberty requires that the three great departments of power should be separate and distinct.

The oracle who is always consulted and cited on this subject is the celebrated Montesquieu. If he be not the author of this invaluable precept in the science of politics, he has the merit at least of displaying and recommending it most effectually to the attention of mankind. Let us endeavor, in the first place, to ascertain his meaning on this point.

The British constitution was to Montesquieu what Homer has been to the didactic writers on epic poetry. As the latter have considered the work of the immortal bard as the perfect model from which the principles and rules of the epic art were to be drawn, and by which all similar works were to be judged, so this great political critic appears to have viewed the constitution of England as the standard, or to use his own expression, as the mirror of political liberty; and to have delivered, in the form of elementary truths, the several characteristic principles of that particular system. That we may be sure, then, not to mistake his meaning in this case, let us recur to the source from which the maxim was drawn. . . .

On the slightest view of the British constitution we must perceive, that the legislative, executive, and judiciary departments are by no means totally separate and distinct from each other. . . .

From these facts by which Montesquieu was guided it may be clearly be inferred that . . . he did not mean that these departments ought to have no partial agency in, or no control over the acts of each other. His meaning, as his own words import . . . can amount to no more than this, that where the whole power of one department is exercised by the same hands which possess the whole power of another department, the fundamental principles of a free constitution, are subverted. . . .

Federalist 48 | February 5, 1788

To the People of the State of New York:

It was shown in the last paper that the political apothegm there examined does not require that the legislative, executive, and judiciary departments should be wholly unconnected with each other. I shall undertake, in the next place, to show that unless these departments be so far connected and blended as to give to each a constitutional control over the others, the degree of separation which the maxim requires as essential to a free government can never in practice be duly maintained.

It is agreed on all sides that the powers properly belonging to one of the departments ought not to be directly and completely administered by either of the other departments. It is equally evident that none of them ought to possess, directly or indirectly, an overruling influence over the others, in the administration of their respective powers. It will not be denied that power is of an encroaching nature, and that it ought to be effectually restrained from passing the limits assigned to it. After discriminating, therefore, in theory, the several classes of power, as they may in their nature be legislative, executive, or judiciary, the next and most difficult task is to provide some practical security for each, against the invasion of the others. What this security ought to be is the great problem to be solved.

Will it be sufficient to mark, with precision, the boundaries of these departments, in the constitution of the government, and to trust to these parchment barriers against the encroaching spirit of power? This is the security which appears to have been principally relied on by the compilers of most of the American constitutions. But experience assures us that the efficacy of the provision has been greatly overrated; and that some more adequate defense is indispensably necessary for the more feeble, against the more powerful, members of the government. The legislative department is everywhere extending the sphere of its activity, and drawing all power into its impetuous vortex.

The founders of our republics have so much merit for the wisdom which they have displayed, that no task can be less pleasing than that of pointing out the errors into which they have fallen. A respect for truth, however, obliges us to remark that they seem never for a moment to have turned their eyes from the danger to liberty from the overgrown and all-grasping prerogative of a hereditary magistrate, supported and fortified by a hereditary branch of the legislative authority. They seem never to have recollected the danger from legislative usurpations, which, by assembling all power in the same hands, must lead to the same tyranny as is threatened by executive usurpations.

In a government where numerous and extensive prerogatives are placed in the hands of a hereditary monarch, the executive department is very justly regarded as the source of danger, and watched with all the jealousy which a zeal for liberty ought to inspire. In a democracy, where a multitude of people exercise in person the legislative functions, and are continually exposed, by their incapacity for regular deliberation and concerted measures, to the ambitious intrigues of their executive magistrates, tyranny may well be apprehended, on some favorable emergency, to start up in the same quarter. But in a representative republic, where the executive magistracy is carefully limited, both in the extent and the duration of its power; and where the legislative power is exercised by an assembly, which is inspired, by a supposed influence over the people, with an intrepid confidence in its own strength; which is sufficiently numerous to feel all the passions which actuate a multitude, yet not so numerous as to be incapable of pursuing the objects of its passions, by means which reason prescribes; it is against the enterprising ambition of this department that the people ought to indulge all their jealousy and exhaust all their precautions.

The legislative department derives a superiority in our governments from other circumstances. Its constitutional powers being at once more extensive and less susceptible of precise limits, it can, with the greater facility, mask, under complicated and indirect measures, the encroachments which it makes on the coordinate departments. It is not unfrequently a question of real nicety in legislative bodies, whether the operation of a particular measure will, or will not, extend beyond the legislative sphere. . . . Nor is this all . . .the legislative department alone has access to the pockets of the people. . . .

The conclusion which I am warranted in drawing from these observations is that a mere demarcation on parchment of the constitutional limits of the several departments is not a sufficient guard against those encroachments which lead to a tyrannical concentration of all the powers of government in the same hands.

Federalist 51 | February 8, 1788

To the People of the State of New York:

To what expedient, then, shall we finally resort for maintaining in practice the necessary partition of power among the several departments, as laid down in the constitution? The only answer that can be given is that as all these exterior provisions are found to be inadequate, the defect must be supplied, by so contriving the interior structure of the government as that its several constituent parts may, by their mutual relations, be the means of keeping each other in their proper places. . . .

In order to lay a due foundation for that separate and distinct exercise of the different powers of government, which to a certain extent is admitted on all hands to be essential to the preservation of liberty, it is evident that each department should have a will of its own; and consequently should be so constituted that the members of each should have as little agency as possible in the appointment of the members of the others. Were this principle rigorously adhered to, it would require that all the appointments for the supreme executive, legislative, and judiciary magistracies should be drawn from the same fountain of authority, the people, through channels having no communication whatever with one another. Perhaps such a plan of constructing the several departments would be less difficult in practice than it may in contemplation appear. Some difficulties, however, and some additional expense would attend the execution of it. Some deviations, therefore, from the principle must be admitted. . . .

It is equally evident that the members of each department should be as little dependent as possible on those of the others, for the emoluments annexed to their offices. Were the executive magistrate, or the judges, not independent of the legislature in this particular, their independence in every other would be merely nominal.

But the great security against a gradual concentration of the several powers in the same department, consists in giving to those who administer each department the necessary constitutional means and personal motives to resist encroachments of the others. The provision for defense must in this, as in all other cases, be made commensurate to the danger of attack. Ambition must be made to counteract ambition. The interest of the man must be connected with the constitutional rights of the place. It may be a reflection on human nature that such devices should be necessary to control the abuses of government. But what is government itself, but the greatest of all reflections on human nature? If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions.

This policy of supplying, by opposite and rival interests, the defect of better motives, might be traced through the whole system of human affairs, private as well as public. We see it particularly displayed in all the subordinate distributions of power, where the constant aim is to divide and arrange the several offices in such a manner as that each may be a check on the other that the private interest of every individual may be a sentinel over the public rights. These inventions of prudence cannot be less requisite in the distribution of the supreme powers of the state.

But it is not possible to give to each department an equal power of self-defense. In republican government, the legislative authority necessarily predominates. The remedy for this inconveniency is to divide the legislature into different branches; and to render them, by different modes of election and different principles of action, as little connected with each other as the nature of their common functions and their common dependence on the society will admit. It may even be necessary to guard against dangerous encroachments by still further precautions. As the weight of the legislative authority requires that it should be thus divided, the weakness of the executive may require, on the other hand, that it should be fortified. . . .