Byrd rule
Definition
The Byrd Rule blocks "extraneous" provisions, meaning ones without real budget effect, outside committee jurisdiction, or that touch Social Security, from being included in a reconciliation bill. The Senate parliamentarian decides what counts as extraneous, and 60 votes are needed to waive the ruling.1
Why it matters
Reconciliation only bypasses the filibuster for genuine budget measures, so the Byrd Rule is the main check preventing a majority party from using a fast-track budget bill to rewrite unrelated policy. Because one unelected official makes the calls, disputes over the ruling often become fights over the process itself rather than the underlying policy.
Seen in the wild
During Senate consideration of the 2025 One Big Beautiful Bill Act, the parliamentarian struck multiple provisions as extraneous under the Byrd Rule, including the bill's own official title, forcing Republicans to rework sections before final passage.2