“The Buffett Rule says that multi-millionaires should pay at least the same percentage of their income in taxes as middle-class families do,” Biden will say. “The Romney Rule says the very wealthy should keep the tax cuts and loopholes they have, and get an additional, new tax cut every year that is worth more than what the average middle-class family makes in an entire year.”

Biden will rip Romney for proposing “another $250,000 in tax cuts to the average millionaire. … These are tax cuts to people who didn’t ask for them, who don’t need them, and who know the nation can’t afford them.”

The speech marks a shift from stumping specifically for the relatively modest Buffett Rule in ostensibly “official” White House events to making a pitch for the broader fall campaign as a “stark choice” of more tax cuts for the rich or rolling back the ones they already have.