With House Democratic leaders poised to introduce and pass a massive appropriations bill today covering funding for nearly every federal agency, Republican staffers and outside interest groups prepared for a frenetic race to figure out what is in the bill before it gets to the president’s desk.

Claiming they have been locked out of final drafting of the massive spending measure, Republicans are planning to assemble a network of experts — one staffer called it a “virtual butcher shop” — to dissect what are likely to be hundreds of pages of legislation, looking for earmarks.

Both the House and Senate have passed new rules this year governing the disclosure of earmarks in spending bills, but the omnibus appropriations bill is moving as an “amendment between houses” — the House taking up amendments made by the Senate — which would be exempt from the earmark disclosure rules.

The House Rules Committee last week approved a rule that would allow Appropriations Chairman David Obey (D-Wis.) to introduce the bill Tuesday and take it to the floor the same day, circumventing normal procedures that would require at least 72 hours’ notice before a bill goes to the House floor.

Rules Committee Republicans sent a letter to Obey last week asking him to commit to publishing a list of earmarks when the omnibus bill is released. The GOP members had offered an amendment on Thursday that would have required Obey to publish a list of earmarks, but that amendment was defeated.

“They have the power to require this list to be provided as the rules state that it should be on every other bill,” said Jo Maney, spokeswoman for the Rules Committee Republicans. As of press time Monday, Maney said the GOP members had received no reply to their letter, and Democratic staff on the Appropriations Committee did not reply to requests for comment.

Late Monday, Obey was hinting that he might gut the bill of all its earmarks, as well as key Republican funding priorities, in response to White House complaints that Congress was trying to increase spending.

But GOP sources said they doubted the bill would be introduced without any earmarks, and even if Obey claimed the bill was clean, they would still need to read it to make sure.

“We are assembling a ‘butcher shop,’” said Brain Kennedy, spokesman for Minority Leader John Boehner (R-Ohio). “We are going to have counsels and policy experts from every committee of jurisdiction scouring the bill.”

Kennedy said the effort will involve House and Senate GOP staff, and will coordinate with outside advocacy groups as well. “We are going to have a mountain [of paper] to dig through in a very short amount of time,” Kennedy said. “The more experts we have scouring through legalese the better.”

Jim Specht, spokesman for Appropriations ranking member Jerry Lewis (R-Calif.) said that with Republicans excluded from the final drafting of the bill, the fear is that “you won’t know what [earmarks are] left in the bill until after the President signs it.”

Ed Frank of Americans for Prosperity said “the taxpayer watchdog groups are ready to scour whatever omnibus comes out whenever it comes out,” looking in particular for the “egregious earmarks” like the Woodstock museum in New York. Frank said a number of the anti-earmark groups — including Taxpayers for Common Sense, the National Taxpayers Union and Citizens Against Government Waste — are likely to “divide the labor a little bit in sort of an informal ‘porkbusters coalition’ … you take these pages, I take those pages” in order to analyze the bill as quickly as possible.

Conservatives in the Senate said they fully expect some new earmarks and policy changes to be slipped into the massive bill. “That’s what they said on the Defense bill,” one GOP aide notes, adding that appropriators and leadership from both chambers inserted millions in new earmarks during the conference talks on that measure.

A Senate GOP aide said the process for combing through the bill will be “something like the immigration battle where we have staffers sequestered to their rooms with coffee and doughnuts” and a section of the bill to be analyzed.

Sean Kevelighan, spokesman for the White House Office of Management and Budget, said the process will pose a major challenge for the White House as well. “The OMB staff is among the best and brightest the administration has to offer, but going through thousands of pages of legislative text that will undoubtedly have numerous passages of complex pork-barrel earmark language will make things difficult for sure,” Kevelighan wrote in an e-mail Monday. “It’s certainly not in the best interest of the taxpayers.”

But Democrats said much of the fault lies with the White House and its refusal to negotiate spending levels with Democrats. The administration has repeatedly threatened to veto spending bills that exceed the budget targets the president has set.

Senate Appropriations Chairman Robert Byrd (D-W.Va.) issued a statement on Monday blasting Bush for putting “political posturing” ahead of the legislative process. “It is extraordinary that the President would request an 11 percent increase for the Department of Defense, a 12 percent increase for foreign aid, and $195 billion of emergency funding for the war, while asserting that a 4.7 percent increase for domestic programs is fiscally irresponsible,” Byrd said in the statement.