Former Sen. Russ Feingold (D-Wis.) called on his colleagues Wednesday to follow up on their upcoming vote on the Buffett Rule and allow the Bush tax cuts to expire.

"A stunning new report came out just this week: Citizens for Tax Justice found that 26 giant corporations -- with total revenue well over $200,000,000,000 -- haven't paid a cent in taxes over the last four years," Feingold wrote in an email to Progressives United, the anti-Citizens United organization he founded last year. "In order to have a fair country, a country where the voices of average people matter as much in government as the voices of the super wealthy, we need to close the loopholes that let corporations get away without paying taxes and let the disastrous Bush tax cuts persist."

Feingold's campaign is in partnership with progressive advocacy group CREDO Action, which is collecting signatures for an online petition.

"In the next few days, you'll be hearing a lot of politicians in Washington DC talk about the Buffett Rule, which if passed would ensure that millionaires pay at least 30 percent in taxes on their income," the petition reads in part. "But it's important that we be clear that the Buffett Rule is not a substitute for rolling back the Bush tax cuts, which along with disastrous wars of choice, are responsible for the last decade's spike in our national debt."

Former President George W. Bush made a rare public appearance Tuesday to argue against raising taxes on the wealthy, saying the move would hurt job creation. The tax cuts, passed during his first term, are set to expire at the end of the year.