The bill, a centerpiece of the president’s push for economic equality, is intended to insure the wealthy contribute more in taxes.
The legislation is also phased in for Americans making anywhere between $1 million and $2 million.
Reid said that failing to raise taxes on the wealthiest Americans to even the playing field was "class welfare, not warfare," as Republicans have charged.
"Our legislation would have protected 99 percent of small-business owners," Reid said.
He went on to say that "it would have been a small but meaningful step" toward covering the country's economic deficit.
Immediately after Reid's remarks, Senate Minority Leader Mitch McConnell (R-Ky.) took to the floor and reiterated criticism he lobbed at President Obama a day earlier, saying that Obama is more interested in political gimmicks than legislating.
Republicans have criticized Democrats' push to raise taxes on the wealthy as a political stunt that's unlikely to go anywhere because legislation like the Buffett Rule is likely to die in the GOP-controlled House even if it passed the Senate.
"We've got a president that's more concerned with looking like he's doing something than actually doing what's needed to challenge the problems that we face," McConnell said. "I mean, weren't these kinds of gimmicks and stale talking points the kinds of things President Obama campaigned against four years ago?"
McConnell also charged that Obama is more interested in "pointing the finger" than fixing the country's problems.
"They need a president who thinks about solving a problem. A president who thinks solving a problem involves more than giving a speech about it and pointing the finger at whatever doesn't poll well that particular day," McConnell said. "The sad truth is it's all politics, all the time in this White House. They're out of ideas. They've got nothing new to offer."