The rule was named after billionaire investor Warren Buffett who has famously said that he paid a lower tax rate than his secretary. Democrats held that millionaires should share the burden of mounting government fiscal pressure.

　　Economic fairness is the "defining issue of our times", Obama said in an address at Florida Atlantic University, adding that U.S. people are better off when everybody gets a fair shot and everybody does a fair share.

　　Nearly one-quarter of all U.S. millionaires pay a lower tax rate than millions of middle-income taxpayers currently, figures from the White House showed.

　　"In this country, prosperity has never trickled down from the wealthy few. Prosperity has always come from the bottom up, from a strong and growing middle class," Obama told a group of students and faculty.

　　"The rich got much richer. Corporations made big profits. But we also had the slowest job growth in half a century" partly due to the tax cut policies rolled out in the George W. Bush administration which has benefited the wealthy, he contended.

　　Wars in Afghanistan and Iraq, former President George W. Bush' s tax cuts, economic stimulus measures under the Obama administration to tide over the economic downturn, and ballooning entitlements expenses in an aging society all contributed in a major way to the spiking U.S. national debt surpassing 15 trillion U.S. dollars.

　　The push for the "Buffett Rule" was the White House's latest effort to portray Obama as being more in touch with middle-class voters. The speech came one week before the Senate's scheduled vote on a bill that would require U.S. taxpayers with an annual income of one million dollars or more to pay an income tax rate of at least 30 percent.