Resolving Legislative Differences in Congress: Conference Committees and Amendments Between the Houses. Congressional Research Service. Elizabeth Rybicki. Updated May 22, 2019
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.
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