The President held another Buffett rule event today in Washington, featuring a series of millionaires and their secretaries.

The people who have joined me here today are extremely successful. They’ve created jobs and opportunity for thousands of Americans. They’re rightly proud of their success. They love the country that made their success possible, and most importantly, they want to make sure that the next generation, people coming up behind them, have the same opportunities that they had.

They understand, though, that for some time now, when compared to the middle class, they haven’t been asked to do their fair share. And they are here because they believe there is something deeply wrong and irresponsible about that.

At a time when the share of national income flowing to the top 1 percent of people in this country has climbed to levels we haven’t seen since the 1920s, these same folks are paying taxes at one of the lowest rates in 50 years. In fact, one in four millionaires pays a lower tax rate than millions of hardworking middle-class households. And while many millionaires do pay their fair share, some take advantage of loopholes and shelters that let them get away with paying no income taxes whatsoever — and that’s all perfectly legal under the system that we currently have.

While the Buffett rule is a pretty modest fix, you can tell from how it’s tying up the opposition in knots that it’s a fairly potent policy from a political standpoint. Josh Barro’s piece in Forbes goes on about how arbitrary it all is, which isn’t totally wrong, but we have arbitrary elements of the tax code, like the alternative minimum tax, already. In fact, this is just a souped-up version of the AMT, one which should probably be combined with it and indexed properly so that it does the job the AMT was supposed to do – limiting deductions to ensure some fair payment on the part of the very rich. Barro seems to be saying that he would rather do some other kind of tax reform, so we shouldn’t do this one. That’s nice for when he rules the world, but it’s not much of a rationale against the Buffett rule.

Karl Rove’s group is trying an even worse tactic, with a petition asking Obama and Buffett to pay more in taxes voluntarily, if they don’t like the tax code. This kind of “neener neener” politics is so small, and at this point I don’t think it fools anybody.

If you want to criticize the Buffett rule, there are probably avenues open to you. The fact that it only impacts people making over $1 million in income, with a phase-in such that the full impact won’t hit earners until they make over $2 million, shows how narrow our tax argument has become in this country. Democrats and Republicans agree on 99.8% of the tax code, to play this out logically (actually less – roughly 1 in 700, according to these IRS numbers). Both of them have their reasons for wanting to pretend that the differences are wider. But both want to keep the Bush tax cut levels for 98% of the public, both want to keep most of the tax credits. Only on this narrow patch of millionaires and billionaires do we have that much of a difference.

When you’re playing on that turf, you cannot credibly say that the Buffett rule is about “investment in the future.” Please. Even under the widest standard, where the Bush tax cuts are extended totally, the Buffett rule doesn’t take in more than $16 billion a year. This is about fundamental fairness – and being more principles-based, that’s why it’s succeeding politically – but it’s not some massive reworking of the tax code to the benefit of the broad mass of citizens. It’s a tweak.

I appreciate that the President acknowledged that today. He said, rightly, that “the notion that it doesn’t solve the entire problem doesn’t mean that we shouldn’t do it at all.” And if you combine it with an expiration of the Bush tax cuts at the high end, you’re getting closer to something with import.

But the barriers there are significant, and the President has already shown himself willing to deal on them once. Even in this speech, he saw fit to emphasize that “I’ve cut taxes for middle-class families each year that I’ve been in office. I’ve cut taxes for small business owners not once or twice, but 17 times.” We aren’t in the midst of a backlash against the tax revolt. We’re still experiencing that initial revolution.