Resolving Legislative Differences in Congress: Conference Committees and Amendments Between the Houses. Elizabeth Rybicki, Specialist on Congress and the Legislative Process, February 15, 2018.

“The Constitution requires that the House and Senate approve the same bill or joint resolution in precisely the same form before it is presented to the President for his signature or veto. To this end, both houses must pass the same measure and then attempt to reach agreement about its provisions.The House and Senate may be able to reach agreement by an exchange of amendments between the houses. Each house has one opportunity to amend the amendments from the other house, so there can be Senate amendments to House amendments to Senate amendments to a House bill. House amendments to Senate bills or amendments are privileged for consideration on the Senate floor; Senate amendments to House bills or amendments generally are not privileged for consideration on the House floor. In practice, the House often disposes of amendments between the houses under the terms of a special rule reported by the Rules Committee. The Senate sometimes disposes of House amendments by unanimous consent, but the procedures associated with the exchange of amendments can become complicated. Alternatively, the House and Senate can each disagree to the position of the other on a bill and then agree to create a conference committee to propose a package settlement of all their disagreements. Most conferees are drawn from the standing committees that had considered the bill initially. The House or Senate may vote to instruct its conferees before they are appointed, but such instructions are not binding. Conferees generally are free to negotiate in whatever ways they choose, but eventually their agreement must be approved by a majority of the House conferees and a majority of the Senate conferees. The conferees are expected to address only the matters on which the House and Senate have disagreed. They also are expected to resolve each disagreement within the scope of the differences between the House and Senate positions. If the conferees cannot reach agreement on an amendment, or if their agreement exceeds their authority, they may report that amendment as an amendment in true or technical disagreement. On the House and Senate floors, conference reports are privileged and debatable, but they are not amendable. The Senate has a procedure to strike out portions of the conference agreement that are considered, under Senate rules, to be “out of scope material” or “new directed spending provisions.” The House also has a special procedure for voting to reject conference report provisions that would not have been germane to the bill in the House. After agreeing to a conference report, the House or Senate can dispose of any remaining amendments in disagreement. Only when the House and Senate have reached agreement on all provisions of the bill can it be enrolled for presentation to the President..”