Editor's note: John Avlon is a CNN contributor and senior political columnist for The Daily Beast. He is the author of "Wingnuts: How the Lunatic Fringe Is Hijacking America."
(CNN) -- Compromise has come to Washington, and the all-or-nothing activists on either side are not happy.
Incoming House Speaker John Boehner doesn't even like to say the word -- it gives him the heebie-jeebies. Even so, compromise has come in the form of an 83-15 vote in the Senate -- one of the most lopsided of the Obama era -- in favor of extending all the Bush tax cuts as well as unemployment benefits and middle class-friendly incentives such as college-tuition tax credits and a payroll tax holiday.
It's a balanced package that promises to boost the economy's recovery while attempting to set a new tone in Washington. And despite the outcry from professional partisans, a Gallup Poll last week showed that even 52 percent of Democrats supported extending all the tax cuts as well as 71 percent of independent voters.
The downside is its impact on the deficit -- $857 billion over the next 10 years, according to the Congressional Budget Office. And this concern has created some fascinating political bedfellows. We're seeing philosophical fault lines erupt on the Republican side while liberal Democrats have started invoking the sanctity of fiscal responsibility. Strange days indeed.
Republicans made full extension of all the tax cuts their line in the sand for negotiations. But now that President Barack Obama agreed to a compromise with their demand, despite his personal opposition to the policy, some conservatives have buyers' remorse. In part, this is the reflexive result of two years of "No-bama" strategy -- they just can't bring themselves to support anything with which the president also agrees.
But the more interesting internal struggle inside conservatism amounts to a full-on crisis of faith. Throughout the Bush years, Republicans acted as if -- in the infamous words of Vice President Dick Cheney -- "deficits don't matter." They argued a supply-side theology approach to the economy in which tax cuts always paid for themselves.
This new round of hand-wringing over the bipartisan compromise points to an implicit acknowledgement that not all tax cuts automatically pay for themselves. This is a triumph of math -- an essential victory on the road to long-term deficit reduction.
Liberal Democrats have also articulated newfound faith in fiscal responsibility as they try desperately to throw themselves in front of the tax compromise. From Sen. Bernie Sanders, a self-described democratic socialist, to members of the Congressional Black Caucus, liberal leaders have warned about the top-rate extension's devastating impact on the deficit.
This would sound a lot more convincing if it didn't contradict their actions over the past Congress. More convincing are liberals' traditional arguments about the fairness of the failure to tax hikes on Americans making more than 250,000 per household. And despite Democrats anger at the estate tax compromise, the money lost is only equivalent to .1% of spending this year, according to the budget office.
Most of these legislators represent Democratic-dominated districts with an endless appetite for federal dollars. The essential goodness of government spending is a key element of their political philosophy.
For all the newfound talk about fiscal responsibility from unexpected corners, there are signs that the spending status quo stumbles on. Exhibit A is the $1.2 trillion that the spending bill winding its way through Capitol Hill contains. Its 9,000 pages contain at least 6,000 separate earmarks totaling some $8 billion requested by Democrats and Republicans alike. It's the congressional equivalent of a pre-Christmas holiday spending spree with your money.
As for the seasonal spirit of compromise, keep an eye out for the START treaty hearing that is expected to begin this week. A strategic priority for the Obama administration, the nuclear arms treaty with Russia has been held up by a small number of conservative senators despite strong support for ratification from every living former secretary of state as well as top military brass. Former President George H.W. Bush has weighed in favor as well.
For those of you keeping score at home, it's a question of whether hyper-partisan gamesmanship will outweigh national security considerations. It should be an easy call -- instead it's a key test of the new spirit of compromise.
Skeptics can be forgiven for questioning the sincerity or sustainability of bipartisan compromise, especially given that the object of compromise to date has been on the relatively pain-free front of tax cuts and increased government spending. But I'll be looking for conservatives and liberals to make good on their deficit concerns in the new year. After the holiday stimulus splurge, it will be time for the federal government to go on a serious diet for our long-term fiscal health.
The opinions expressed in this commentary are solely those of John Avlon.