Barack Obama has clearly warmed to the fight over taxes and income inequality, which is wonderful to see. At a campaign event yesterday, he responded with derision to Romney’s accusations that his policies were based on envy of the rich. He archly suggested that Warren Buffett and Bill Gates aren’t motivated by class envy. Mockingly, he reassured Americans that he, Buffett, and Gates would survive if their taxes went up.

Romney’s argument is so simplistic, and reeks so strongly of a wealthy plutocrat lording it over those he sees as his inferiors, that it’s worthy of Obama’s scorn. But Obama also made some serious points. He’s 

This has nothing to do with envy. It has everything to do with math. We’ve got to make choices. Americans understand — if I get a tax break I don’t need, and a tax break the country can’t afford, then one of two things are gonna happen: either it’s going to add to our deficit, or somebody else is going to have to make up the difference…. [Emphasis added]

As Greg Sargent points out, Obama has also embraced the argument that the rich should pay higher taxes to ensure the continued functioning of the system that led to their own success:

Each of us is only here because somebody, somewhere, felt a responsibility to each other and to our country and helped to create all this incredible opportunity that we call the United States of America. Now it’s our turn to be responsible. And it’s our turn to leave an America built to last for the next generation.

I’m so glad that Democrats are finally embracing this message. Plenty of liberals, myself included, have been saying this for years, of course. But we owe an enormous debt of gratitude to Elizabeth Warren for bringing it into the mainstream.

Obama has a legitimate argument for why soaring inequality is harmful to our nation, and why we should increase taxes on the rich. Mitt Romney has name calling, and adamant demands that nobody ever discuss income inequality except in “quiet rooms.” His “arguments,” such as they are, deserve every bit of scorn Obama heaped on them.