Veering from the playbook.

House Republicans, just days after standing their ground, decided instead to head home for Christmas dinner.

So much for the principles that brought them to power in 2010. So much for ending business as usual in the nation’s capital.

But their language changed by the end. Gone was the moral outrage, the appeals to end the mindless spending that was bankrupting the nation. This week, the House Republican talking points led with the insistence that America’s working men and women deserved more than a two-month payroll tax holiday. Somehow, the Tea Party-spawned House Republicans had morphed into demagoguing Proletarian heroes.

But this was an important moment. After all, when the current House majority seized the reins, they were clear that their mission was to curtail spending as the singular path to curbing massive fiscal deficits, while not impeding the morally righteous task of cutting taxes. Specifically, the House Republicans changed “Paygo” rules that had been in effect for many years—whereby tax and spending measures must be budget-neutral over a 10-year period, as scored by the Congressional Budget Office—to provide instead that such constraints should not apply to tax cuts.

This perspective—that deficits are not a function of the mix of revenues and expenditures but rather a function of spending alone—is a odd vestige of the Reagan era, when cutting taxes emerged as the sine qua non of the modern Republican Party and liberated the GOP from its stodgy traditions of fiscal prudence and school marmishness. At the time of the Reagan revolution, when marginal tax rates where high, one could make a fairly reasoned argument of the supply-side premise, that cutting taxes would increase revenues. But that argument was bound up in the facts and economics of that era, and only attained that status of a moral imperative in the ensuing years.

But in the debate regarding extending the payroll tax cut, for reasons that are unclear, the House Republican did not merely forsake their rule that tax reductions are morally self-justifying, they went to the mattresses to demand that they be paid for like any other legislation of Democrat-inspired spending.

Then, suddenly, they got up off the mattresses, changed their votes and went home.

Fast forward to late next year and the implications of the House action looms large. At the end of 2012, the Bush-era tax cuts are set to expire just like the payroll tax cut that was just extended. Under the House Paygo rules, Republicans would no problem demanding that such tax cuts remain permanent, despite the $4 trillion of projected costs over ten-years. But the payroll tax debate should cast the stance of the House Republicans in a new light. This month, for the first time in recent memory, the Republicans took a stand against tax cuts because of the fiscal implications of those cuts.

For the first time in recent memory, Milton Friedman and the Republican Party of my grandfather were redeemed. This was a significant point that should not be lost.

Because the simple truth is that to extend the Bush tax cuts is wrong.

Little if anything has been said in the public debate over those tax cuts to remind the public about why they had an expiration date to begin with. After all, changes in the tax code tend to be eternal, and ability to rely on the rules of the tax system is a bedrock principle of our economy. But the Bush-era tax cuts had to expire if they were going to comply with the fiscal rules in place when the cuts were enacted into law. To meet the ten-year Paygo scoring rules, the Bush-era tax cut legislation provided for rates to return to the levels in effect in 2001 after seven years in order to pay for the largesse that was bestowed upon taxpayers over the period the cuts were to be in effect.

Oddly, in the debate over extending those tax cuts, up until now the Democrats and Republican essentially had to act under different political rules. Democrats, because they are the party of wanton over-spending and fiscal profligacy, had to justify how extending the tax cuts would be somehow fiscally justifiable. Republicans, because their brand includes the long-defunct notion that they are the party of fiscal prudence, felt no such constraint, and they have felt free to argue that the cuts be made permanent, whatever the fiscal impact might be.

The argument in Congress that the Bush-era tax cuts should be extended has given the lie to the notion that Congress is subject to any rules, even the ones it places on itself. The argument that tax rates should not be increased in the face of a recession is utterly disingenuous. Those arguing to gut the 2001 and 2003 tax bills now would be doing so regardless of our economic condition.

Look back at the historical record. Even as the Bush-era tax cut legislation was being considered, Republican leaders assured their base that by 2010 those cuts would be made permanent, as the Republicans pledged from the outset to attack as taxers any who would let the cuts expired. That is to say, even at the moment of the original legislation, those who supported those tax cuts eschewed any intention of adhering to the fiscal rules that Congress had imposed on itself. At the time, the cynicism was breathtaking. But as political calculation, it was prescient.

This month, House Republicans veered from the Republican orthodoxy on cutting taxes without offsets in favor of their Tea Party anti-deficit principles when they demanded spending cuts if the payroll tax cut was to be extended. For the first time in recent memory, Republicans returned to pre-Reagan principles and demanded that tax cuts be paid for.

A cynic might argue that this was not a change from the Republican playbook. They might suggest instead that we have seen the emergence of a codicil to the principle that tax cuts are morally self-justifying that suggests that such cuts must be paid for if the benefit accrues to working class Americans. Or perhaps the House leadership simply got caught up in needing to oppose anything that Democrats supported, and lost sight of the fact that they were in the odd position of opposing a tax cut.

In acting to demand that the payroll tax cut extension be paid for, will the House Republicans apply the same rule to extending the Bush-era tax cuts? That would be a game changer. But it is more likely that the House Republicans will get their act together, and once again the $4 trillion cost—and profound hypocrisy—of extending the Bush-era tax cuts will be subordinate to the higher moral principle of cutting taxes—without regard to cost.