In the "regular order" -- which is to say, the Senate's customary procedure -- the time for debate is unlimited, and if a minority of 40 senators refuses to stop talking, then you need 60 of them to invoke the rule that shuts the others up and allows the bill to come to vote. If you don't have 60 votes to break the filibuster, it doesn't matter if you have 50 votes to pass the bill.
The reconciliation process, by contrast, limits debate to 20 hours and bypasses the filibuster altogether. It was instituted to ensure that minority obstruction couldn't block important business like passing a budget or reducing the deficit. But it was misused. At least, Robert Byrd thought so. He saw all manner of "extraneous" amendments and legislation sneaking beneath the radar of the reconciliation process. Rather than being used to reconcile the budget or reduce the deficit, it was being used to short-circuit the filibuster (much, one might say, like the filibuster itself, which was being used not to lengthen debate on legislation but kill that legislation altogether).
Imagine you want to run health reform through the reconciliation process. Here's how it works: Congress includes reconciliation instructions in the budget. Those instructions direct certain committees -- say, the Finance Committee and the Health, Energy, Labor, and Pensions Committee -- to produce health-reform legislation hitting certain spending targets by a certain deadline. Once finished, the legislation is tossed back to the Budget Committee, which staples it together into an omnibus bill and sends it to the floor of the Senate for 20 hours of debate followed by an up-or-down vote.
...If you want to know why we do not today have a 50-vote Senate, the Byrd rule is the reason. The Byrd rule imposes a set of sharp constraints on the reconciliation process, limiting what is considered appropriate for reconciliation. The basic theory of the Byrd rule is that any legislation considered under the budget reconciliation process should principally affect federal revenues. A tax cut, for instance, can be considered under the reconciliation process. A new federal holiday cannot. But between those two examples sit crucial ambiguities.
The Byrd rule states that legislation is unfit for reconciliation if it "produce changes in outlays or revenue which are merely incidental to the non-budgetary components of the provision." I asked Jim Horney, a budget expert at the Center for Budget and Policy Priorities, how you define "merely incidental." And what, exactly, is a "provision"?
He sighed. A provision, he said, is "not defined anywhere. It goes well below a title or section of a bill and even below a paragraph. But exactly what it is nobody knows." And the Senate rules offer no more clarity on the definition of "merely incidental." Asked if anyone had developed an accepted meaning, Horney seemed almost apologetic. "No," he said. "Absolutely not." ...
more:
http://prospect.org/cs/articles?article=the_fifty_vote_senate