In order to become law, a bill must pass both chambers of Congress in technically and substantively identical form. Of course, it is not always the case that a bill “cleanly” passes both the House and Senate without amendment or differences between the two chambers. As such, the Congress must reconcile differences between their respective bills before passing the legislation to the President for signature. There are three primary ways by which the Congress achieves this – amendment exchange between the chambers, through a “Conference Committee,” or through informal negotiation.

In an “amendment exchange,” a legislative measure may be sent between the House and Senate, with each chamber amendment the amendments of the other in the hope that one will agree to the other’s proposal. Bill text may be amended between chambers in two degrees. When opportunities for amendments are exhausted, one chamber must accept the other’s position – or the legislation “dies.” Of course, the two chambers may reach agreement at any stage of the amendment exchange process if one concurs in the amendment of the other or recedes from its own amendment (particularly if that amendment is not acceptable in the other chamber).

If the House chooses to amend and pass, as amended, legislation sent from the Senate, it is sent as a “message” to the Senate. The message is privileged, with no debate on proceeding to its consideration. The legislation is then debatable, subject to cloture as it may be filibustered, and amendable – with amendments need not being germane. Generally, the “amendment tree” may be “filled” to control the scope and content of amendments. The Senate may disagree to the House amendment and either “kill” the bill or request conference; concur with the amendment and pass the legislation as amended by the house; or –if a second-degree amendment is still allowed – concur with a further amendment and send the legislation back to the House.

In the House, the Senate’s “message” is also privileged, without debate on the question of its consideration. The Senate amendment is debatable, under a one-hour rule, and amendable – with all amendments needed to be germane and debated under a five-minute rule. Customarily, the Senate message is taken up under a rule to control the proceedings, including limiting the number, scope, and content of possible amendments. Like in the Senate, the House may disagree to the Senate amendment and either “kill” the bill or request conference; concur with the amendment and pass the legislation as amended by the Senate; or – if a second-degree amendment is still allowed – concur with a further amendment and send the bill back to the Senate.

Notably, in the House, if the Senate’s amendments are non-germaine or major in scope, or fall within the jurisdiction of a House committee that had not originally considered the bill, the Speaker is often likely to refer the bill to committee for consideration. Moreover, if the Senate amendments include any authorization, appropriation, or revenue provisions that House rules require to be considered in Committee of the Whole, it is not immediately in order for the House to consider the Senate amendments. However, the House floor manager may circumvent this procedural “roadblock” by asking for unanimous consent to concur in the Senate amendments or concur in the Senate amendments with House amendments. Alternatively, the Speaker may entertain a motion to suspend the rules, or the Rules Committee may report a special rule on the bill’s consideration that makes in order a motion to concur with or without amendment.

If the chambers cannot or do not come to agreement through amendment exchange, they may request for and go to “Conference.” The “Conference Committee” is intended to enable negotiations between representatives of both chambers to find compromise on their bills’ differences. After a chamber requests or agrees to a conference, it selects Members as “conferees” to represent the body. The selection of who may participate in the conference is, understandably, strategically important. Both chambers may move to “instruct” their conferees, directing them to insist on or recede to certain positions. Instructions are not binding in either chamber. In the Senate, the “motion to instruct” is debatable and amendable; in the House, it is debated under the one-hour rule.

As Conference Committees are created to resolve differences between the chambers’ bills, conferees have no authority to change matters that are not in disagreement. Nor may they include provisions that fall outside the range of options defined in a House position at one “extreme” and a Senate position at the “other.” However, there are otherwise little-to-no rules governing procedure in the Conference Committee, in stark contrast to the various rules of procedure guiding legislative activities in the House and Senate. This enables either “formal” or “informal” practices, proceedings, and negotiations to occur in different Conference committees.

Upon conferees reaching full agreement on compromise language, a conference report is prepared which indicates how each amendment in disagreement has been resolved. The report must be signed by a majority of House and a majority of senate conferees. The report is, by rules of both chambers, required to be accompanied by a joint explanatory statement that describes the nature of disagreements addressed by conferees. The chamber that agreed to the conference normally acts first on considering the report, and the first (though not the second) chamber to consider a conference report may recommit the report to conference.

Conference reports are privileged in both chambers, unamendable, and debatable. In the House, a conference report is considered under the one-hour rule. Points of order, including against a “tainted” report in which conferees are perceived to have exceeded their authority, are permitted. However, the House can approve the conference report under suspension of the rules, which does not allow points of order on the floor; alternatively, the Rules Committee may propose that the House approve a special rule waiving any or all points of order against the report or its consideration. In the Senate, debate on conference reports may be limited by unanimous consent or cloture; waivers on points of order may be secured with a three-fifths vote threshold. If the Senate does not waive a scope point of order, errant material must be dropped, with the Senate then voting on whether to send back to the House what remains. The same applies to “Byrd Rule”-relevant provisions; if a point of order is not waived, the Senate then considers the motion of sending back to the House a proposal striking “new matter” or “new directed spending provisions.” The vote to agree to a conference report normally completes a chamber’s action on the measure.

Finally, it should be noted that differences between the chambers’ bills’ may be informally negotiated for resolution in lieu of a formal conference committee. Interested Members, their staff, or Committee staff may, as work in one or both chambers nears or reaches completion of floor action on a measure, informally compare differences between their bills and negotiate resolution to their differences. If a tentative agreement on compromise is acceptable, a conference committee is therefore unnecessary – with these compromises instead reflected and achieved through responsive amendment exchange between the chambers.