Today, President Obama will travel to Florida to give a speech pushing for Senate passage of the Buffett Rule, which will require millionaires who are paying low tax rates to pay an overall rate of 30 percent. The measure is key to Obama’s push to make tax fairness — and the broader ideological clash between him and Romney over government’s role in shoring up the middle class — central to Campaign 2012.

Polls show public support for Obama’s push for higher taxes on the rich. But that doesn’t mean tax fairness will drive swing voters, particularly if the recovery sputters. So how will the tax debate play within the context of the presidential race? How much will it matter?

Yesterday’s big Times piece on the Rove-founded group Crossroads GPS’s coming anti-Obama ad blitz contained a telling clue. In it, Crossroads founder Steven Law acknowledges that Obama is winning the tax debate, because it feeds the idea that Romney favors an “economic plutocracy” in which the deck is stacked against the middle class. But he also characterized Obama’s case as follows: “His argument is: ‘The reason you feel bad is not because I’ve been an inadequate president but because the rules of the game are stacked against you.’ ”

Keep an eye on this. The GOP strategy will be to characterize Obama’s push for tax fairness as an effort to distract from his own failures on the economy and divert public anger over the economy away from the president. The GOP hopes to neutralize the tax fairness issue by separating it from the economy’s performance. But Obama’s case is that there is no separating the fairness issue from the economy’s performance or from people’s economic suffering. He is selling an overall vision that includes pushing for more revenues from the wealthy to facilitate government investment in the economy and in shoring up the middle class, and combatting inequality not just out of basic fairness, but also to facilitate economic growth.

And that’s why this number, in today’s Post poll, may be important:

What do you think is the bigger problem in this country — unfairness in the economic system that favors the wealthy, or over-regulation of the free market that interferes with growth and prosperity?

Unfairness: 52

Over-regulation: 37

This doesn’t mean Obama doesn’t face a very challenging situation. What it does mean: The race may turn largely on whether voters make their choice based on their sense of the candidates' overall visions, priorities, values, and whose interests they are looking out for, which may favor Obama, or on the unemployment rate this fall, which may favor Romney. This is what the push for the Buffett Rule is all about.

* Obama’s general election message about the economy: Relatedly, David Axelrod vows a continuing push for the Buffett Rule, and previews the message it supports:

“We’re going to have a big debate about the economy. That big debate is going to be, who’s going to promote an economy in which the middle class can grow? In which hard work is rewarded, responsibility is rewarded, everybody [plays] by the same rules from Main Street to Wall Street? And the question is which of these two candidates is more likely to promote that kind of economy.”

* Obama leading Romney as gender gap widens: Today’s Post poll also finds that Obama leads Romney among registered voters, 51-44. The key, though, is that Obama holds double-digit leads over Romney on who would do a better job protecting the middle class and addressing women’s issues. Obama leads Romney by 18 points among women.

Though head-to-head polling this far out is not necessarily meaningful, these findings go to the heart of the clash of visions and priorities that is developing between the candidates.

The most important numbers right now are Obama’s approval ratings: his overall approval is 50 percent, but his approval on the economy is upside down at 44-54 and on gas prices it stands at 28-62.

* The “empathy factor” favors Obama: Chris Cillizza and Aaron Blake dig into the Post’s polling and find this:

Asked which man “better understands the economic problems people in this country are having”, 49 percent of people said Obama while 37 percent named Romney...

Among electorally critical independents, Obama enjoys a 47 percent to 35 percent edge over Romney. Women favor Obama over Romney by 20 points on the empathy question.

This, too, is a reminder why the Obama campaign wants this election to be about a clash of values and overall visions.

* Obama campaign links Buffett Rule to Romney: The Obama campaign has a new memo which links the Buffett Rule, Romney’s low tax rates, and his refusal to release his tax returns:

Mitt Romney opposes the Buffett Rule — he thinks millionaires and billionaires should keep paying lower tax rates than middle-class families. In fact, Romney himself isn’t paying his fair share — in 2010, Romney paid a tax rate of only 13.9 percent, well below the rate paid by many middle-class Americans. And with each week, new questions are raised about whether Romney took unusual steps to avoid paying his fair share in taxes. Yet we can’t answer those questions because he simply refuses to release enough of his tax returns to give a clear picture of his finances.

As I’ve been saying, Senate Republicans may vote unanimously to protect the wealth of their likely nominee, who is worth $250 million and pays lower tax rates than many middle class taxpayers do.

* Ryan-for-Veep buzz grows louder: More and more Republicans and insiders appear to be treating this as a genuine possibility, yet another sign that both sides appear absolutely convinced that Ryan — and the larger vision he represents — are a political winner for them.

* Inside the Dems’ strategy for recalling Walker: Andy Kroll notes a fascinating angle on the story: collective bargaining has all but receded into the background as Walker’s dishonesty about his intentions, his deep budget cuts and the overall damage his policies would do to the middle class have come to the fore.

* Revisiting Obama’s “attack” on the court: Jonathan Cohn has a nice reponse to all the outrage about Obama’s supposed “attack” on the court. Cohn notes that the specific legal references that have been so heavily criticized were about making a broader point: “By invalidating the Affordable Care Act, the Supreme Court would be resurrecting a vision of constitutionally limited government that, quite rightly, went out of fashion a long time ago.”

* Obama still has a gay marriage problem: Steve Benen explains why his good record on gay rights may not protect him from the coming controversy over gay marriage and the party’s platform language.

* And a GOP member of World’s Greatest Deliberative Body calls Obama “stupid”: Relatedly, the news that Chuck Grassley called Obama “stupid” for his remarks about the Court is only the latest example of a surprisingly persistent view on the right that this dimwitted President wouldn’t be where he is today if it weren’t for his trusty teleprompter.

What else?