WASHINGTON -- The debt-reduction supercommittee may well fail in its assignment to find at least $1.2 trillion in savings. The anticipatory finger-pointing has already begun. Yet as the clock ticks, I find myself uncharacteristically optimistic, for two reasons.

In the short term, nothing concentrates the mind like a sequester -- especially one that hits defense spending. Even more important, because the planned cuts would not take effect for a year and could be undone, nothing concentrates the political mind like an election -- and lawmakers on both sides of the aisle seem truly worried about the electoral implications of failure. The public is already disposed to throw the bums out, and if the bums can't even manage a down payment on debt reduction, the risk they will suffer that fate becomes even greater.

This fear explains the remarkable and underappreciated seismic shift that is the basis for my longer-term optimism: Republicans are beginning the process of breaking free of the no-new-taxes spell that has been cast over their party for the last few decades. No matter what happens or fails to happen before the supercommittee's deadline this week, the era of lip-reading and unalterable pledges on revenue is nearly over.

Amazingly, Pennsylvania Republican Sen. Pat Toomey, former head of the rabidly anti-tax Club for Growth, proposed a deal that included -- gasp! -- a net increase in tax revenue from the current level.

Just as amazingly, he was joined by Texas Republican Rep. Jeb Hensarling, former head of the ultra-conservative Republican Study Committee. When Hensarling served on the Simpson-Bowles debt reduction commission, he voted against the recommendations, declaring that "further tax increases on the American people should be off the table."

I don't mean this in a disrespectful way, but pigs are flying here, folks.

Democrats argue that the GOP offer shouldn't be taken seriously. They dismiss the proposal as a ploy to promote the appearance of Republican reasonableness. Republicans, in this view, presented Democrats with an offer they couldn't afford to take -- and that Republicans knew wouldn't be accepted.

It's true that the GOP offer represents a tax increase only in the artificial -- and unaffordable -- context of assuming that the Bush tax cuts are continued in their entirety, rather than ending at the end of next year. In comparison to letting the tax cuts for the wealthiest expire, as Obama and congressional Democrats want, the Republican offer represents a $500 billion tax cut.

Perhaps, but the fact remains: The once-sacred principle of not raising taxes -- any taxes, ever -- has been breached. Not by some namby-pamby Republicans in name only, but by serious movement conservatives with unimpeachable anti-tax credentials. If they are willing to raise taxes now, they, or other Republicans, cannot decree such increases off the table in the future.

The Republicans' anaphylactic allergy to taxes is by no means cured. In the event that the supercommittee strikes a deal, expect an uproar, especially among House members panicked at the thought of being accused of reneging on the no-new-tax pledges extracted by anti-tax activist Grover Norquist.

But the cracks in Fortress Norquist are showing, and they are more than hairline. The pledge-signing natives have long been restless and looking for an escape hatch. Toomey and Hensarling have provided one.

A quip commonly attributed to George Bernard Shaw comes to mind. We've established -- and, again, no disrespect intended; this is an excellent development -- that Republicans are willing to raise taxes. From now on, we're just haggling over price.