Reconciliation is a special fast track that lets certain budget legislation pass the Senate with a simple majority, bypassing the 60-vote filibuster, but only for measures that genuinely change spending or revenue.
Created by the Congressional Budget Act of 1974, reconciliation lets Congress bring existing law into line with the spending and revenue targets set in its annual budget resolution. Its defining feature: in the Senate, debate is limited and cloture is not needed, so 51 votes can pass it.
Reconciliation is reserved for fiscal policy, changes to spending, revenue, or the debt limit. It cannot be used as a vehicle for general legislation, which is the trade-off for skipping the filibuster.
To keep reconciliation from becoming a loophole, the Senate's Byrd Rule lets any senator strike provisions deemed 'extraneous,' for example ones with no real budgetary effect, or whose budget impact is merely incidental to a policy change. Stripped provisions, sometimes called 'Byrd droppings,' fall out unless 60 senators vote to keep them, which would defeat the purpose.
Congress can generally pass only a small number of reconciliation bills tied to each budget resolution, and the rules constrain measures that would raise deficits beyond the budget window. Reconciliation is powerful but narrow, which is why major non-fiscal bills still face the 60-vote threshold.