The knock on Romney's plan, which Obama accurately cited, is that Romney has refused to say which tax breaks he would eliminate to pay for the lower rates.
ROMNEY: "What would I cut from spending? Well, first of all, I will eliminate all programs by this test, if they pass it: Is the program so critical it's worth borrowing money from China to pay for it?"
THE FACTS: China continues to be portrayed by Romney and many other Republicans as the poster child for runaway federal deficits. It's true that China is the largest foreign holder of U.S. debt, but it only represents about an 8 percent stake. And China has recently been decreasing its holdings, according to the Treasury Department. Some two-thirds of the $16 trillion national debt is owed to the federal government, with the largest single stake the Federal Reserve, as well as American investors and the Social Security Trust Fund.
OBAMA: "Independent studies looking at this said the only way to meet Gov. Romney's pledge of not ... adding to the deficit is by burdening middle-class families. The average middle-class family with children would pay about $2,000 more."
THE FACTS: That's just one scenario. Obama's claim relies on a study by the Tax Policy Center, a Washington research group. The study, however, is more nuanced than Obama indicated.
The study concludes it would be impossible for Romney to meet all of his stated goals without shifting some of the tax burden from people who make more than $200,000 to people who make less.
In one scenario, the study says, Romney's proposal could result in a $2,000 tax increase for families who make less than $200,000 and have children.
Romney says his plan wouldn't raise taxes on anyone, and his campaign points to several studies by conservative think tanks that dispute the Tax Policy Center's findings. Most of the conservative studies argue that Romney's tax plan would stimulate economic growth, generating additional tax revenue without shifting any of the tax burden to the middle class. Congress, however, doesn't use those kinds of projections when it estimates the effect of tax legislation.
ROMNEY on cutting the deficit: "Obamacare's on my list. ... I'm going to stop the subsidy to PBS. ... I'll make government more efficient."
THE FACTS: Romney has promised to balance the budget in eight years to 10 years, but he hasn't offered a complete plan. Instead, he's promised a set of principles, some of which — like increasing Pentagon spending and restoring more than $700 billion in cuts that Democrats made in Medicare over the coming decade — work against his goal. He also has said he will not consider tax increases.
He pledges to shrink the government to 20 percent of the size of the economy, as opposed to more than 23 percent of gross domestic product now, by the end of his first term. The Romney campaign estimates that would require cuts of $500 billion from the 2016 budget alone. He also has pledged to cut tax rates by 20 percent, paying for them by eliminating tax breaks for the wealthiest and through economic growth.
To fulfill his promise, then, Romney would require cuts to other programs so deep — under one calculation requiring cutting many areas of the domestic budget by one-third within four years — that they could never get through Congress. Cuts to domestic agencies would have to be particularly deep.
But he's offered only a few modest examples of government programs he'd be willing to squeeze, like subsidies to PBS and Amtrak. He does want to repeal Obama's big health care law, but that law is actually forecast to reduce the deficit.
ROMNEY: "Simpson-Bowles, the president should have grabbed that."
OBAMA: "That's what we've done, made some adjustments to it, and we're putting it before Congress right now, a $4 trillion plan."