The argument in one screen
Treaties are not ordinary domestic laws
Hamilton says treaties are agreements between sovereigns, not rules prescribed by a sovereign to subjects in the ordinary legislative way.
The President alone would be unsafe
An elective magistrate serving a short term could be tempted by ambition or avarice in ways that make sole treaty power too risky.
The Senate alone would also be worse
Hamilton thinks Senate-only treaty power would throw away the President's diplomatic advantages and reduce security by excluding executive participation.
President plus Senate gives the best balance
The Constitution's mixed design combines executive fitness for negotiation with a legislative-style check on a power whose effects are law-like and highly consequential.
Why Hamilton thinks treaties belong to a mixed constitutional arrangement
Federalist 74 defended command in war and the pardon power as distinctly executive. Federalist 75 shifts to a harder case. Hamilton says treaty-making does not fall cleanly into either of the ordinary constitutional bins, which is exactly why the Constitution gives it a mixed institutional form.
His first move is classificatory. The power of making treaties is not the execution of existing law, and it is not simply the making of new municipal law either. Treaties have the force of law, but they derive that force from the obligations of good faith between sovereigns.
Not a tidy powers chart. A reminder that constitutional categories sometimes have to bend toward the nature of the thing being done.
“The power of making treaties is plainly neither the one nor the other.”
Hamilton says treaty-making does not fit the ordinary definitions of either legislative or executive power.
“Its objects are CONTRACTS with foreign nations, which have the force of law, but derive it from the obligations of good faith.”
This is Hamilton's defining line: treaties bind like law, but they arise from sovereign agreement rather than ordinary legislation.
“It must indeed be clear to a demonstration, that the joint possession of the power in question by the president and senate would afford a greater prospect of security, than the separate possession of it by either of them.”
Hamilton's institutional conclusion is that shared treaty power is safer than leaving the power wholly with either branch.
How Hamilton argues against the main alternatives
He rejects vesting treaties in the President alone because an elective magistrate of limited duration may be tempted in ways a hereditary monarch is less tempted. Ambition, avarice, and future private vulnerability make sole control too delicate a trust for one temporary executive hand.
He also rejects vesting the power in the Senate alone. That would deprive the Union of the constitutional agency of the President in foreign negotiation and could leave treaty formation exposed to senatorial pique, cabal, or reduced diplomatic weight abroad.
Finally, he rejects broadening the arrangement to include the House or requiring supermajorities of the whole Senate rather than of senators present. Too many actors or too rigid a denominator, he argues, would introduce inconvenience, delay, and the familiar pathologies of impotence, perplexity, and disorder.
He defines treaties as sovereign agreements
Hamilton insists that treaties are contracts with foreign nations, not ordinary commands from a sovereign to subjects.
He wants executive participation but not executive monopoly
The President is the most fit negotiating agent, but not a safe sole possessor of the whole power.
He treats the House as too variable and numerous for this trust
Accurate knowledge of foreign politics, secrecy, and dispatch are not qualities Hamilton expects from a large and fluctuating representative body.
Federalist 75 matters because it shows Hamilton trying to map a real constitutional power onto imperfect categories. He does not force treaties into a neat box just because theory likes neatness. He lets the nature of treaties drive the institutional design.
It also matters because the essay is one of Hamilton's clearest examples of mixed constitutional reasoning. He wants executive energy where negotiation requires it, but he also wants security and restraint where the power has large legal and political consequences.
Why Federalist 75 matters in the larger executive sequence
Federalist 73 and Federalist 74 defended executive independence, veto power, war direction, and mercy. Federalist 75 turns to treaties, where Hamilton says the power itself has a mixed character and therefore calls for a mixed institutional design.
The next essay, Federalist 76, continues with appointments and asks how nomination plus Senate consent can improve the quality of officeholders while checking favoritism. For the wider Publius frame, return to Who wrote the Federalist Papers?.
What to read next
Primary sources and further reading
- The Federalist No. 75 | Founders Online — Hamilton's defense of the treaty-making arrangement as a mixed power shared by the President and Senate.
Related essays by theme
Use Federalist 75 to see why Hamilton thinks treaties need both executive fitness and senatorial restraint
This is the essay to read when you want Hamilton's answer to a difficult design problem: if treaties are neither ordinary laws nor ordinary executive acts, where should that power live in a republic?
Hamilton's argument for a shared treaty power still frames why the Senate is structurally tied to American diplomacy.