According to the US Constitution - Article 1, Section 3:

The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two-thirds of the Members present.

However there is no such clause in regards to issuing the Impeachment and therefore it only requires one-half of the votes in the House of Representatives. What was the historical reason for not requiring a two-thirds vote in the lower chamber as well?

  • 5
    Federalist Paper #65, #66, and #69, all by Hamilton, address impeachment comprehensively, in case anyone else cares to prepare an answer while I celebrate Christmas this evening Dec 18, 2019 at 21:13
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    As far as I know, in all courts there is a lower bar for indictment than conviction. Dec 18, 2019 at 22:09
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    @PieterGeerkens - No, it wasn't Hamiltion and the Papers cited do not address this issue of "representation". He does note that representatives will likely vote based on party-lines. Very prescient.
    – J Asia
    Dec 20, 2019 at 6:30

4 Answers 4


Contrary to popular opinion, the basic model for impeachment as outlined in the U.S. Constitution is not criminal prosecution but rather the process of impeachment existing in the British Parliament subsequent to 1681.

In practice, the Commons would usually select a committee to draw up the charges and create an "Article of Impeachment" for each. Once the committee had delivered the articles to the Lords, replies go between the accused and the Commons via the Lords. If the Commons have impeached a peer, the Lords take custody of the accused; otherwise, Black Rod takes custody. The accused remains in custody unless the Lords allow bail. The Lords set a date for the trial while the Commons appoints managers, who act as prosecutors in the trial. The accused may defend by counsel.

The House of Lords hears the case. The procedure used to be that the Lord Chancellor presided (or the Lord High Steward if the defendant was a peer); but this was when the Lord Chancellor was both the Lords' presiding officer and head of the judiciary of England and Wales. ...

The hearing resembles an ordinary trial: both sides may call witnesses and present evidence. At the end of the hearing the lords vote on the verdict, which is decided by a simple majority, one charge at a time. Upon being called, a peer must rise and declare "guilty, upon my honour" or "not guilty, upon my honour". After voting on all of the articles has taken place, and if the Lords find the defendant guilty, the Commons may move for judgment; the Lords may not declare the punishment until the Commons have so moved. The Lords may then decide whatever punishment they find fit, within the law.

Hamilton makes this explicit in Federalist #65:

The model from which the idea of [impeachment] has been borrowed, pointed out that course to the convention. In Great Britain it is the province of the House of Commons to prefer the impeachment, and of the House of Lords to decide upon it. Several of the State constitutions have followed the example.

As such, the founders were working from a base model in the U.K. of a simple majority in the House of Lords being sufficient for conviction of impeachment.

However, as outlined particularly in Federalist #10 by Madison, the founders were particularly aware of the dangers of both faction and tyranny of the majority.

By a faction, I understand a number of citizens, whether amounting to a majority or a minority of the whole, who are united and actuated by some common impulse of passion, or of interest, adversed to the rights of other citizens, or to the permanent and aggregate interests of the community.

There are two methods of curing the mischiefs of faction: the one, by removing its causes; the other, by controlling its effects.


The inference to which we are brought is, that the CAUSES of faction cannot be removed, and that relief is only to be sought in the means of controlling its EFFECTS.

... When a majority is included in a faction, the form of popular government, on the other hand, enables it to sacrifice to its ruling passion or interest both the public good and the rights of other citizens. To secure the public good and private rights against the danger of such a faction, and at the same time to preserve the spirit and the form of popular government, is then the great object to which our inquiries are directed.

In designing the safeguard of impeachment, the Founders deliberately sought to protect against the tyranny of the majority through faction. In Federalist #66 Hamilton states:

A FOURTH objection to the Senate in the capacity of a court of impeachments, is derived from its union with the Executive in the power of making treaties. ...

This objection has been circulated with more earnestness and with greater show of reason than any other which has appeared against this part of the plan; and yet I am deceived if it does not rest upon an erroneous foundation.

The security essentially intended by the Constitution against corruption and treachery in the formation of treaties, is to be sought for in the numbers and characters of those who are to make them. The JOINT AGENCY of the Chief Magistrate of the Union, and of two thirds of the members of a body selected by the collective wisdom of the legislatures of the several States, is designed to be the pledge for the fidelity of the national councils in this particular.

Finally, in his conclusion, Hamilton first disabuses the notion that the Senate is too large a body to reach a verdict of guilty as their pride, if not their virtue, could surely be counted upon to defend the privileges of the Senate.

So far as might concern the misbehavior of the Executive in perverting the instructions or contravening the views of the Senate, we need not be apprehensive of the want of a disposition in that body to punish the abuse of their confidence or to vindicate their own authority. We may thus far count upon their pride, if not upon their virtue.

He then wraps up by noting that if an offense is so great as to warrant removal from office, and the public ire so great as to make action unavoidable, then the self interest of the Senate would surely compel a sufficient number of that body to act so as to deflect public ire from themselves.

And so far even as might concern the corruption of leading members, by whose arts and influence the majority may have been inveigled into measures odious to the community, if the proofs of that corruption should be satisfactory, the usual propensity of human nature will warrant us in concluding that there would be commonly no defect of inclination in the body to divert the public resentment from themselves by a ready sacrifice of the authors of their mismanagement and disgrace.


It is better that ten guilty persons escape than that one innocent suffer.

  • Sir William Blackstone

Differing Standards for House of Representatives and the Senate

On the question: Why two standards, namely simple majority vs supermajority (two-thirds)?

The answer lies not so much in the intention or deliberations of America's Founding Fathers. So, instead of seeing it as deliberate decision on the part of the Founding Fathers, the better enquiry is to ask, what is the purpose of each requirement (simple- vs super-majority).

If we adopt this perspective, what is the purpose/meaning of each requirement, we can see that a simple majority is the (constitutional) equivalent of "probable cause" or "reasonable suspicion" standard. To convict, on the other hand, the supermajority (two-thirds) by the Senate is clearly a higher (more difficult) standard. Again, using the constitutional equivalency, Senate cannot convict on mere "probable cause" but the standard of "beyond reasonable doubt".

If I can paraphrase into America's context, it takes a lower standard to suspect and charge - impeachment by Representatives by a simple majority. But it takes a lot more to convict - two-thirds of the Senate.

Legal Doctrines Galore

Legal doctrines being what they are (often also how they are expressed and intrepreted) tend to confuse many. My interest in OP's question is to see if I'm still confused having done the reading (too long ago).

Let's start with what this question is not about. It isn't about the legal doctrine of separation of powers. For which, Hamilton's Federalist Paper #66 answers quite succinctly. Neither is it about when to impeach and what instrument Parliament (or in this case, Congress) should use to remove an officer of the Crown or a federal officer in the case of USA.

There are many doctrines referenced in the Federalist Papers, in general, as would be expected in a debate about institutional powers. But I have not read anything in the discussions on explicitly setting out the standard of proof required to impeach and convict a public official, i.e. OP's enquiry.

So, where did this standard or requirement come from?

Lex ex Consuetudo Parliamenti

Latin for law and custom of Parliament. The common law system is, to put it mildly, highly unsatisfying the deeper one gets to its (historical) roots. This is one of those occasions.

"Lex ex consuetendo Parliament" is not criminal nor civil nor even canon law. It is purely the evolved practices of Westminster Parliament, one that only the High Court of Parliament practices.

From Hatsell's Precedents (Precedents of Proceedings in the House of Commons: Relating to Conference and Impeachment):

“That matters moved in Parliament shall be managed, adjudged, and discussed, by the course of Parliament; and in no sort by the Law Civil, or by the Common Law of the Land, used in other lower courts of this kingdom.”

Sir Edward Coke says, “As every court of justice hath laws and customs for its direction, some by the Common Law, some by the Civil and Canon Law, so the High Court of Parliament suis propriis legibus et consuetudinibus consistit. It is by the Lex et Consuetudo Parliamenti, that all weighty matters concerning the Peers of the Realm, or Commons in Parliament assembled, ought to be discussed, ad judged, and determined.”

Indeed all the wisest statesmen and greatest lawyers, through a long succession, from Sir Edward Coke and Mr. Selden, to the Earl of Hardwicke, have, whenever an opportunity has been offered to them, constantly repeated this doctrine.

Source: Preface


Since 1760s at the latest, and very likely earlier, before Blackstone's Commentaries on the Laws of England, it is the heritage of common law system of setting higher standards to convict (as opposed to merely charge or indict). This is to err on the side of caution, lest we convict the innocent (Blackstone's ratio).

How did this come to pass that US adopted this doctrine into their Constitution, resulting in differing standards to impeach by the House of Representative on the one hand, and on the other, a higher standard of two-thirds by Senate to convict?

The answer lies in the law and custom of the British Parliament ('Lex ex consuetendo Parliament').

Since I began with a line from Blacksone's Commentaries, I wonder if it's fitting to end with another:

The president is not Gulliver immobilized by 10,000 tiny cords, nor even a Prometheus chained to a rock of frustration. He is, rather, a kind of magnificient lion who can roam widely and do great deeds so long as he does not try to break loose from his broad reservation.


To avoid partisanship

To be removed from the office by the Congress is a huge stain on someone's life, character and honor. It could also lead to further criminal proceedings. In case of removing President, such act would essentially negate the will of the voters (i.e. the People of US ). Founding Fathers wanted to create checks and balances for executive branch of the government, by they also wanted to avoid partisanship. In the history of US it was not uncommon to have President from one party and majority both in House and in the Senate from another, and Founding Fathers anticipated that even before it happened. To avoid situations were from purely partisan reasons one side uses its political muscle, and to avoid situation were accusers are also the judges, House indicts someone , but Senate must judge him and convict him with 2/3 majority. Hamilton says :

The division of them between the two branches of the legislature, assigning to one the right of accusing, to the other the right of judging, avoids the inconvenience of making the same persons both accusers and judges; and guards against the danger of persecution, from the prevalency of a factious spirit in either of those branches. As the concurrence of two thirds of the Senate will be requisite to a condemnation, the security to innocence, from this additional circumstance, will be as complete as itself can desire.

As we can see, Founding Fathers didn't want to concentrate too much power in the hands of either chamber of Congress, and also shielded accused from "factious spirit" - i.e. partisanship . Only in case of very high crime (treason, murder ... ) , were immorality and guilt of accused is evident to all sides, shall someone be removed from the office.

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    The Founding Fathers could not see into the future, as implied here: "In the history of US it was not uncommon to have President from one party and majority both in House and in the Senate from another." The history of the Republic was ahead of them, not in the rear view mirror. Dec 20, 2019 at 8:46
  • @PieterGeerkens Well, I would say they could "see", or to use proper term, anticipate the future. Considering the system they created, it looks like they paid special attention to prevent "dictatorship of majority" and blind populism. One could even say that they actually preferred gridlock to rushed decisions.
    – rs.29
    Dec 20, 2019 at 8:54
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    Your argument states that the made their decisions based on the history of the Republic, which is impossible. It taints the rest of your post [moderator edit for civility]. Dec 20, 2019 at 8:56
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    @PieterGeerkens Answer edited to clarify the matter.
    – rs.29
    Dec 20, 2019 at 21:22

Congress "indicts" someone. But it is up to the Senate to "convict." Analogously, Congress is a "Grand" Jury and the Senate functions like a "regular" jury. It takes a higher bar for conviction than indictment.

  • Similes and metaphors are only legal argument when grounded in the body of the law. An impeachment is not an indictment - it is an impeachment. The law surrounding each are different, starting from the fact that one is explicitly defined in the constitution stand alone while the other is based on Common Law principles over 1000 years old. Dec 20, 2019 at 6:42
  • As noted in Federalist #65, the model for impeachment is not the courts of law, but the British Parliament: "In Great Britain it is the province of the House of Commons to prefer the impeachment, and of the House of Lords to decide upon it. Several of the State constitutions have followed the example.". Dec 20, 2019 at 6:46
  • Further, the explicit allowing of subsequent criminal prosecution of impeached and convicted person, thus the disallowing of a double jeopardy situation, speaks directly to an impeachment not being likened to a criminal proceeding: "Article I Section 3: ...but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.". Dec 20, 2019 at 6:55

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