At the same time, Senator Robert C. Byrd, Democrat of West Virginia and longtime protector of the prerogatives of the Senate, created a complex set of rules intended to impede those who would dare to use reconciliation to rewrite federal policy rather than produce budget savings.

Image Senator Robert C. Byrd, in 1974, created rules intended to impede a tactic now being explored. Credit... Associated Press

Under the Byrd Rule, provisions where the fiscal consequences are “merely incidental” to the true intent of the legislation can be struck from the bill unless 60 senators vote to waive the rule. Reconciliation measures are traditionally scoured for such provisions, in what is known around the Senate as giving the bill a “Byrd bath.”

Because Republicans would most likely be so incensed that Democrats were trying to force through a sweeping health plan by simple majority vote, they would no doubt challenge many elements of the bill and could strip them out.

“Most of the big public policy stuff, which is really important, would not survive the Byrd Rule,” said Senator Judd Gregg of New Hampshire, the senior Republican on the Budget Committee and someone who could be counted on to use his expertise to make reconciliation as difficult as possible for Democrats.

But there is a potential way around the Byrd Rule as well. Democrats are envisioning an unusual two-track approach. Under this strategy, some of the most contentious elements of the health plan  new taxes and fees as well as savings from Medicare, Medicaid and other federal programs  would be packaged in one bill that could be passed by a simple majority.

A second measure would contain the policy changes and program expansions and would be treated like an ordinary bill, subject to filibuster and amendment. But the thinking is that this legislative sidecar would contain enough popular programs to attract the 60 votes needed to overcome a filibuster. Voilà  a health care bill.

Of course, there are still potential pitfalls, including this one: If some senators are angry that the first bill squeaks through, they might not want to cooperate in providing help to pass the second one, whether they like it or not.