Rep. Tammy Baldwin (D-WI) on Monday urged leaders of the U.S. House of Representatives to bring her legislation to the floor to enact the so-called Buffett Rule.

"As tax day quickly approaches, middle class Americans deserve to know that our tax system has not been rigged against them," she said. "The Paying a Fair Share Act would ensure that middle class workers do not pay a higher tax rate than those earning more than $1 million a year."

The Paying a Fair Share Act would establish the so-called “Buffett Rule,” which would require those earning more than $1 million per year to pay at least a 30 percent effective tax rate on their income. The rule is named after billionaire investor Warren Buffett, who has lamented the fact that he paid a lower tax rate than his secretary.

Republicans have condemned the proposed rule as class warfare and it is unlikely to pass in the GOP-led House of Representatives. Nearly all House Republicans have sworn to fight any and all tax increases.

But Baldwin said the American people "deserve to know where their Representatives stand" on this "critical" issue.

"Our current tax code has been influenced by powerful special interests and includes loopholes and special provisions that allow approximately a quarter of all millionaires to pay lower effective tax rates than millions of middle class families," she explained.

Approximately 94,500 millionaires pay a lower effective tax rate than millions of families earning less than $100,000, according to the Congressional Research Service (PDF).

Senate Majority Leader Harry Reid has announced that the Senate will vote on the legislation on April 16, tax day.