In the US - at the federal and AFAIK the state level - pieces of legislation are put forward in two versions, independently, before the two legislative bodies; each version is discussed, debated and passed independently (correct me if I'm wrong); and then if they both pass, there's this process of reconciliation.

I haven't studied the details of this process, but it seems very weird to me. Shouldn't it be the case that the lower, larger chamber (the House of Representatives) passes legislation, then the upper house (the Senate) ratifies, rejects, or perhaps amends-and-ratifies legislation passed in the lower house?

Specifically, does this somehow originate in the UK's House of Commons vs House of Lords bicamerality?

  • Reading your comments on the answers I think this may be closely related to a previous question. Perhaps you could clarify the difference.
    – user9389
    Commented Nov 10, 2017 at 23:14

4 Answers 4


Both houses can introduce bills because they are intended to have equal power

The United States Congress does not have a lower and upper house, instead it has two separate but equal houses. The House of Representatives represents the people and the Senate represents the states, with equal power of legislation.

James Madison wrote in the The Federalist Papers #39:

The next relation is, to the sources from which the ordinary powers of government are to be derived. The House of Representatives will derive its powers from the people of America; and the people will be represented in the same proportion, and on the same principle, as they are in the legislature of a particular State. So far the government is NATIONAL, not FEDERAL. The Senate, on the other hand, will derive its powers from the States, as political and coequal societies; and these will be represented on the principle of equality in the Senate, as they now are in the existing Congress. So far the government is FEDERAL, not NATIONAL. The executive power will be derived from a very compound source. The immediate election of the President is to be made by the States in their political characters. The votes allotted to them are in a compound ratio, which considers them partly as distinct and coequal societies, partly as unequal members of the same society. The eventual election, again, is to be made by that branch of the legislature which consists of the national representatives; but in this particular act they are to be thrown into the form of individual delegations, from so many distinct and coequal bodies politic. From this aspect of the government it appears to be of a mixed character, presenting at least as many FEDERAL as NATIONAL features.

(emphasis mine)


For a bill to reach the president, both chambers of Congress must pass the same bill. The process of reconciliation is the process by which the two chambers negotiate the differences between two similar bills that have each been passed by one of the chambers.

For example, suppose there is a crime that is punishable by imprisonment for up to 5 years, and the Senate passes a bill saying that the maximum term should be increased to 10 years, while the House of Representatives passes a bill saying it should be increased to 20 years.

There are a few options for the next steps:

  1. Both chambers pass the other chamber's bill; the president then gets to decide which one to sign (logically, if the president signs both, the second one overrides the first and remains in effect).
  2. One chamber passes the other's bill.
  3. Neither chamber passes the other's bill.

The first option is likely to be disfavored because Congress may not want to give the president the power to resolve the discrepancy in this way.

If one chamber tried to pursue the second option, perhaps having changed its mind about the proper penalty for the crime in question, and did so without conferring with the other chamber, there would be a danger that the other chamber would do the same, leading to the first (possibly disfavored) option.

Therefore, the members of the two chambers arrange to communicate about the two bills, usually through the mechanism of a conference committee, to decide which one to pass. Of course, they can instead decide to pursue the third option above and pass neither bill but instead proposing a new bill that "reconciles" the differences. In this example, they might decide to increase the maximum term of imprisonment to 15 years.

In that case, the new bill must be passed by both chambers before it is sent to the president to sign.

As to the origin of legislation, bills may originate in either chamber unless the bill concerns the raising of revenue. Here is section 7 of article 1 of the constitution, where all of this is set out:

Section 7

1: All Bills for raising Revenue shall originate in the House of Representatives; but the Senate may propose or concur with Amendments as on other Bills.

2: Every Bill which shall have passed the House of Representatives and the Senate, shall, before it become a Law, be presented to the President of the United States; If he approve he shall sign it, but if not he shall return it, with his Objections to that House in which it shall have originated, who shall enter the Objections at large on their Journal, and proceed to reconsider it. If after such Reconsideration two thirds of that House shall agree to pass the Bill, it shall be sent, together with the Objections, to the other House, by which it shall likewise be reconsidered, and if approved by two thirds of that House, it shall become a Law. But in all such Cases the Votes of both Houses shall be determined by yeas and Nays, and the Names of the Persons voting for and against the Bill shall be entered on the Journal of each House respectively. If any Bill shall not be returned by the President within ten Days (Sundays excepted) after it shall have been presented to him, the Same shall be a Law, in like Manner as if he had signed it, unless the Congress by their Adjournment prevent its Return, in which Case it shall not be a Law.

3: Every Order, Resolution, or Vote to which the Concurrence of the Senate and House of Representatives may be necessary (except on a question of Adjournment) shall be presented to the President of the United States; and before the Same shall take Effect, shall be approved by him, or being disapproved by him, shall be repassed by two thirds of the Senate and House of Representatives, according to the Rules and Limitations prescribed in the Case of a Bill.

  • While this is very informative (really!) it doesn't answer my question. Why can each of the houses pass its own legislation (or pre-legislation)? I don't understand the rationale nor the historical reasons.
    – einpoklum
    Commented Nov 10, 2017 at 22:53
  • I take exception to your #1 option. There can't ever be a situation where each chamber passes the other chamber's version of the same bill and both make it to the President. It must be reconciled first. And even if it happened (and the President signed both), both would become law. It would be an ambiguity that courts would have to resolve.
    – Wes Sayeed
    Commented Nov 11, 2017 at 2:28
  • @einpoklum Why couldn't each chamber pass its own bill? There's no mechanism to stop it. There doesn't need to be a rationale; it's just how the system works, as laid out in the constitution: one house proposes a law by passing a bill. If the other house agrees, by passing the same bill, the bill is sent to the president for signature. Inherent in that system is the possibility that the chambers have different ideas about what laws should be passed, which may even contradict one another. Conference committees are one mechanism to deal with the contradiction.
    – phoog
    Commented Nov 11, 2017 at 5:16
  • @WesSayeed what mechanism exists to prevent such a situation? Reconciliation can only occur if a conflict is identified, which isn't necessarily easy to do given the complexity of some legislation. I also don't understand why you think there would be an ambiguity: if the President signs a law saying that the penalty is 10 years and then subsequently signs a law saying that the penalty is 20 years, the second law supersedes the first. It doesn't matter whether the second law is signed five years after the first or five minutes.
    – phoog
    Commented Nov 11, 2017 at 5:20

There may be times when a President wished that he or she had the ability that the UK Prime Minister has to create new laws. The framers of the constitution seemed to equate "efficiency" with "oppression". They deliberately made it hard for the government to create new laws. The hope is that any new laws will have had full consideration.

The process is similar in the USA and UK. The principle is that both houses must agree on the exact text of a bill, and an amended bill is returned to the other house for further consideration. A bill that doesn't have the support of both houses will not become law; this is an important safeguard.

In the UK the lower house has the ability ultimately to overrule the unelected upper house (because of the Parliament Act 1911), but this power did not exist in 1776. In the UK the approval of the executive (the Queen) is a formality. In the USA the President's veto is real.

So the USA system has more safeguards against bad legislation: The Senate cannot be overruled, and the President must also approve. The framers of the US system were certainly aware of the UK parliament but chose to turn on all the safeguards. They wanted a system where the government couldn't easily create laws to oppress the citizens.

  • 1
    The US has more barriers against legislation; and they work against "good" and "bad" legislation just the same. Also, the reference to -werror is not clear even for those of us who know what -werrro means. Anyway, +1.
    – einpoklum
    Commented Nov 10, 2017 at 22:57
  • Yes, that analogy was rather forced. -- deleted
    – James K
    Commented Nov 10, 2017 at 23:02
  • 2
    "UK the lower house has the ability ultimately to overrule the unelected upper house": only because of the Parliament Act 1911. Commented Nov 11, 2017 at 0:10

A single bill must pass both houses.

Everyone wants to have input into it.

This means almost everything is subject to amend-and-ratify. So differences between the final versions are going to need to be addressed anyway. It makes sense for everyone to start working on whatever issue is being addressed concurrently because it's often a long and hard process.

The versions are generally not really independent. At least leadership will be meeting regularly to consider what will happen next throughout the process.

My understanding is that they did intend to imitate the UK parliament, trying to instill higher class into the Senate through age, appointment and longer terms.

  • This doesn't answer my question, it just explains how there are work-arounds for the formal weirdness of independent (proto-)legislative abilities of both chambers.
    – einpoklum
    Commented Nov 10, 2017 at 22:54

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