Yet the deal shepherded by House Speaker John Boehner and Democratic leader Nancy Pelosi carries power just the same. It would buck the popular impression that Washington can't accomplish anything at all. It also would provide a template for deals on other issues, if only Republicans and Democrats were willing to use it.
Read MoreWhat first mover Ted Cruz will mean for the race
Democrats agreed to accept spending cuts affecting health care providers like rehabilitation hospitals and skilled nursing facilities. The "Medigap" policies some seniors buy to supplement Medicare would be barred from covering their deductibles for doctor visits, since deductibles help restrain consumption of health services.
Republicans agreed to accept revenue increases. They not in the form of tax increases, but rather in the form of Medicare premiums for beneficiaries with incomes above $133,500.
And both parties agreed to add two-thirds of the package's cost to the federal deficit—setting aside the insistence on "budget neutrality" that they sometimes invoke selectively to block priorities of the other side. Requiring tax or spending "offsets" to cover all the cost, rather than just $70 billion of it, would have sunk the package.
There are good reasons that Republicans and Democrats laid down some of their traditional political weapons in this case. Lawmakers have grown weary of repeatedly being forced to pass "doc fix" bills to overcome restraints on doctor fees from a 1997 deficit reduction bill that hasn't worked as intended by then-President Bill Clinton and the GOP Congress.
Read MoreBrawl over budget will frame 2016 presidential race
In 21st century Washington, of course, good reasons are often insufficient to propel what once was the routine business of government. Typically only the raw compulsion of statutory deadlines does the trick anymore.