The 15% Question: Why Mitt Romney's Tax Rate Matters Mitt Romney stammered on Monday night when debate moderators asked him whether he'd release his tax returns. I hadn't planned on releasing tax records, because the law requires us to release all of our assets, all the things we own. It's a pretty full disclosure," he said. But, you know, if that's been the tradition, and I'm not opposed to doing that, time will tell. But I anticipate that most likely I am going to get asked to do that around the April time period, and I'll keep that open. It wasn't actually an answer - he's already been asked - and worse yet, it was much more awkward than Romney's usual Pomade pivot from unwelcome questions. On Tuesday he gritted his teeth and gave an answer that shed more light on his reluctance. "What's the effective rate I've been paying?" he said when prompted by reporters in South Carolina. It's probably closer to the 15 percent rate than anything because my last 10 years, my income comes overwhelmingly from some investments.... The answer confirmed Michael Scherer's guestimation in early October: Because of capital gains, Romney pays a tax rate that's much lower than what most U.S. wage earners will ever enjoy. Read more about Romney's campaign. Romney might have hoped to delay his tax disclosures until April to soften the political impact - the nomination race will be wrapped up by then and the general election won't yet be in full swing. He may have also been shooting to release 2011 records, not prior years, which wouldn't be ready until tax day. But whenever it came out, it was bound to shape the race. For Democrats, this is the perfect campaign issue. It lies at the intersection of the personal, professional and political identities they plan to foist on Romney in the general election: the privilege they hope will make it hard for voters to relate to Romney, the erstwhile career in private equity that they hop will taint him as a economic predator rather than a turnaround artist, and the regressive tax policies they hope can drive a wedge between the Republican party and the middle class. The Democratic machine is in high dudgeon. Back in October, Priorities USA Action, a super PAC run by a former Obama aide, seized on Scherer's story and cut an ad twisting the so-called Buffett Rule - named for the legendary Omaha investor's famous observation that he pays a lower tax rate than his secretary - into the Romney Rule, trying to hit all three points: out-of-touch, corporate, unfair. They brought the video back in the wake of Romney's remarks. Even GOP rival Newt Gingrich, ever bitter about Romney's success, got in a lick. "Since my flat tax is 15 percent, I'm thrilled at the idea, I assume this afternoon he will endorse my flat tax proposal and have every American pay the rate he paid," he said Tuesday. I think that would be terrific. Read "Does Mitt Romney Have a Prayer with Evangelicals?" The tax rate issue also serves as a direct tie-in to the debate over practices at Bain Capital, and not just during Romney's tenure. As the New York Times explained last month, Romney didn't just amass his wealth there in the '90s. Much of his investment income, on which he continues to pay a low rate, flows from Bain's deals: Though Mr. Romney left Bain in early 1999, he received a share of the corporate buyout and investment profits enjoyed by partners from all Bain deals through February 2009: four global buyout funds and 18 other funds, more than twice as many over all as Mr. Romney had a share of the year he left. He was also given the right to invest his own money alongside his former partners. Because some of the funds and deals covered by Mr. Romney's agreement will not fully wind down for several years, Mr. Romney is still entitled to a share of some of Bain's profits. All of this plays into Romney's weakest area. Even when he's making sense, he often has a tin ear when it comes to wealth and corporatism. In discussing his financial disclosures Tuesday, he referred to hundreds of thousands of dollars he's earned in speaking fees as "not very much." But he's not deaf to the tax rate issue, and his defense is right there in his campaign's economic plan: While most of the GOP candidates want to zero out the capital gains rate, Romney would only lower it for families making $200,000 or less. In other words, he wouldn't lower his own taxes. But the rate he pays is already really low. And now that Romney's put it out there, Democrats won't let anyone forget it. Read "Mitt Romney's Top 10 Gaffes.")