Welcome back to work, Mitt!

The Mittster had barely gotten out of bed on Monday morning, following a weeklong vacation at his lakefront mansion in New Hampshire, before the liberal attack dogs began snapping at his well-tanned ankles. In his column in the Times, Paul Krugman demanded more information about Romney’s “very mysterious” financial holdings in offshore tax havens, such as Switzerland and the Cayman Islands. Appearing on MSNBC’s “Morning Joe,” Robert Gibbs, the former White House press secretary, also brought up these exotic locales, saying, “The American people deserve to know if he’s sheltering this money somewhere, or quite frankly, if he’s not paying the taxes he owes and the only way to do that is to release more tax returns.”

A few hours later, President Obama himself appeared at the White House and practically dared Romney to oppose his plan for the Bush tax cuts: extending the cuts for all households with an income below two hundred and fifty thousand dollars, while allowing Bush’s giveaways to those earning more than that to expire at the end of this year. “We don’t need any more trickle-down economics,” Obama said. “We need policies that grow and strengthen the middle class.”

If you suspect the whole thing was a blatant attempt to change the subject from Friday’s dismal job figures, award yourself a gold star courtesy of David Axelrod. In the “O Chicago” school of politics that Rupert Murdoch warned Romney about last week, the best form of defense is offense, and when it comes to attacking Romney there’s no better area to focus on than income taxes—his, and the rest of the country’s. But still, writing the whole thing off as a political stunt would be an error.

Behind the theatrics, two important and opposing principles are at stake: the principle that rich people should pay substantially more of their income in taxes, which underpinned American politics for almost a century; and the principle that a politician who endorses a tax increase of any kind is inviting certain defeat, which has dominated politics in Washington for much of the past decade. Obama is endeavoring to give new life to the first principle and overturn the second. If he succeeds, there will be a great irony—Romney and his byzantine personal finances will have played a significant role in saving the progressive-tax system.

The Obama campaign isn’t just trying to change the subject from jobs—although that is certainly part of it. It is rolling out a political strategy designed to make a debate about taxes that is potentially hazardous to Democrats into a much more favorable debate about just how rich and out-of-touch Mitt Romney is. (If your answers are “very” and “totally,” award yourself another gold star courtesy of Axelrod.) It’s a clever enough strategy, but one that is not without risks for the White House.

Two years ago, in the runup to the 2010 midterms, President Obama made exactly the same demands of Congress—and they backfired. The Republicans ignored the fact that he was calling for the preservation of a net tax cut for ninety-eight per cent of American households and depicted him as an old-fashioned tax-and-spend liberal. The message worked. To quote Obama, the Democrats got “a shellacking.”

What is different this time? Privately, some Democrats in Congress worry that the answer might be not very much. Nancy Pelosi and Chuck Schumer, both of them acutely sensitive to what happened in the midterms, reportedly favored making the cutoff for tax increases at least a million dollars, rather than two hundred and fifty thousand. In sticking with the lower figure, Obama and his advisers are betting that there is something very different between now and 2010—and that difference is Romney’s name at the top of the Republican ticket. Thanks to his absurdly low federal tax rate, his offshore accounts, and his refusal to disclose more than a couple of years of income-tax filings, Team Obama believes that Romney can be turned into a poster boy for everything that’s wrong with how the U.S. government raises money from its citizens.

The Mittster, bless his bright red jet ski, has invited it upon himself. He isn’t just “Mr. Fourteen Per Cent,” he’s a walking loophole. The scandalous “carried interest” deduction for managers of hedge funds and private equities; the artificially low rates on income derived from capital gains and dividends; the fancy accounting tricks, including the use of overseas accounts—Romney and family benefit from all of these (perfectly legal) blights on the tax system.

True, the “news” that he has parked some of his money offshore isn’t new at all, and it isn’t very “mysterious” either. The 2010 tax return that he put out earlier this year revealed the existence of his Swiss bank account, his investment company incorporated in Bermuda, and the fact that some of his Bain Capital related investments are held in Cayman Islands trusts. But the Obama campaign was merely waiting for an opportune time to exploit these revelations; and what better moment could there be than the first business day after the third straight set of poor jobs figures?

The Romney campaign’s response was predictable. “Unseemly and disgusting” was the phrase one flack used to describe Gibbs’s suggestion that the G.O.P. candidate was a serial tax avoider. Following Obama’s appearance at the White House, the Romney campaign put out another statement saying, “Americans are struggling in a ‘zombie economy’ and President Obama’s only answer is to pass one of the largest tax hikes in history.”

Thus, the battle lines are drawn. Which side wins will help shape the tax system for years to come. If it’s Obama, we are heading back towards the Clinton era, which, as the President pointed out, was a period of low unemployment and record budget surpluses. If it’s the G.O.P., the anti-tax brigade will have won another huge victory, with some pretty dire consequences for inequality and fiscal solvency.

Photograph by Alex Wong/Getty Images.