All GOP hopefuls at Aug. debate said would turn down a hypothetical deficit-reduction deal that had 10 times as many spending cuts as tax increases.

Gerald Seib writes in The Wall Street Journal:

In the great casino of national politics, here's the current action: Both parties are busy doubling down their bets on taxes, the subject that figures to define the partisan divide in the 2012 campaign.

By proposing to pay for his new jobs program with tax increases, as he did last week, and by proposing numerous tax hikes to reduce the giant federal deficit, as he did Monday, President Barack Obama is laying down a populist marker.

Facing an economy in need of stimulation now and deficit reduction in the long run, he is saying the sensible formula is for the wealthy and corporations to pay more to right the ship and keep it afloat.

For his part, House Speaker John Boehner has declared tax increases "off the table" for deficit reduction, redrawing the same battle lines seen during the long and frustrating summer of debt negotiations.

And, of course, there was that scene of all the Republican presidential candidates agreeing at an August debate in Ames, Iowa, that, because of their opposition to any tax hikes, they'd turn down a hypothetical deficit-reduction deal that had 10 times as many spending cuts as tax increases.

Republicans are saying that the nation's economic and fiscal distress has made them less likely, not more, to support more taxes.

This tax divide has become the core philosophical debate three years into a horrible economic downturn. The split doesn't bode well for finding any consensus on economic matters in Washington this year, but it sets up a great ideological clash in next year's voting.

At some level, of course, every election is about taxes. The level of taxation determines the size of government the country can afford, and size of government goes a long way toward determining the role government plays in the economy and the society.

But the picture is more stark than normal, for two reasons. First, the yawning deficit has made the choices for dealing with it—spending cuts or tax increases—more acute. And second, the Republican presidential primary race has made the tax question more pronounced: At the heart of the tax debate lies the question of whether the tax cuts passed under President George W. Bush—one of the GOP's proudest accomplishments of the past decade—will survive the presidential campaign intact or not.

That has only reinforced what had become a fairly uniform view on taxes among Republicans, which, in turn, reflects a fairly strong ideological consensus within the party.

Indeed, one of the principal problems President Obama faces at the moment is that ideological convictions are running stronger among Republicans than among the president's Democrats.

In the most recent Wall Street Journal/NBC News poll, for example, 68% of Republicans identify themselves as conservative—half of them calling themselves "very conservative"—while just 31% of Democrats call themselves liberal.

William Galston, a former Clinton White House aide now at the Brookings Institution, says this disparity means the polarization between the two parties is "asymmetrical."

He says Republicans are more ideologically unified and therefore feel more strongly about their core issue, low taxation, while Democrats aren't as ideologically united and therefore not as ardent on their core issue, defense of entitlement programs.

"That's the difference between the two parties," Mr. Galston says. "A substantial number of Democrats would be willing to endorse a grand bargain involving both taxes and entitlements, while very few Republicans would be willing to join them."

In a nutshell, that explains much of the past six months in Washington, and nothing said or done Monday suggested much of a change.

Republicans essentially charged that Mr. Obama's tax-the-rich idea for deficit reduction is class warfare: "Pitting one group of Americans against another is not leadership," said Mr. Boehner. Retorted the president: "This is not class warfare. It's math."

The effort to paper over this split now will be handed to the congressional supercommittee set up in the summer debt-reduction deal to find at least $1.2 trillion in additional deficit reductions. But it's becoming clear that the real referendum comes in the 2012 campaign.

And both parties enter the fight seeing opportunity but running risks on the tax question.

Republicans think that with government spending at roughly 25% of gross domestic product, the highest level since World War II, Americans have turned a corner on the size of government and see squeezing taxes as a way to throttle down Washington.

The danger for the GOP is that independent swing voters don't consider the tax question as the kind of central issue as do Republican primary voters.

More than half the independent voters in the Journal/NBC News poll said they considered it acceptable to attack the deficit with a combination of spending cuts and tax increases.

Democrats, meanwhile, think that with government revenue running at about 15% of GDP, the lowest level since 1950, Americans in the middle don't consider the country overtaxed. And Mr. Obama knows he's delivering a tax message badly wanted by his party's base: Three-quarters of them say they are happy to see the Bush tax cuts ended for wealthier Americans.

The danger for Democrats? The history of their candidates entering presidential campaigns proposing tax increases isn't so encouraging.