A food safety bill that has burned up precious days of the Senate’s lame-duck session appears headed back to the chamber because Democrats violated a constitutional provision requiring that tax provisions originate in the House.

By pre-empting the House’s tax-writing authority, Senate Democrats appear to have touched off a power struggle with members of their own party in the House.

The Senate passed the bill Tuesday, sending it to the House, but House Democrats are expected to use a procedure known as “blue slipping” to block the bill, according to House and Senate GOP aides.

Section 107 of the bill includes a set of fees that are classified as revenue raisers, which are technically taxes under the Constitution. According to a House GOP leadership aide, that section has ruffled the feathers of Ways and Means Committee Democrats, who are expected to use the blue slip process to block completion of the bill.

“We understand there is a blue slip problem, and we expect the House to assert its rights under the Constitution to be the place where revenue bills begin,” the GOP aide said.

The blue slip could lead to one of two likely outcomes. Senate Majority Leader Harry Reid (D-Nev.) could simply drop the issue and let the next session of Congress start from scratch, a strategy that would allow him time in the lame-duck session to tackle other last-minute priorities, such as the expiring 2001 and 2003 tax cuts, a long-term continuing resolution, an immigration bill and a repeal of the military’s ban on openly gay service members.

Or he could try to force the issue in the Senate after the House passes a new version of the bill. But in order to do that and still tackle the other issues, he would need a unanimous consent agreement to limit debate.

According to Senate GOP aides, a unanimous consent agreement is all but certain to be a nonstarter because the bill’s chief opponent, Sen. Tom Coburn (R-Okla.), will not agree to such a deal.