WASHINGTON -- A procedural problem is adding possibly significant hurdles to the drive in Congress to approve sweeping changes in immigration policy.
The difficulty stems from a Senate bill that would create a guest worker program and a path to citizenship for many of the illegal immigrants in the United States.
Participants in the guest worker program would pay income taxes, and illegal immigrants would be required, as part of the legalization process, to pay back taxes and new fees.
But the Constitution gives the House sole authority to originate bills that include revenue measures, and it allows any House member to object if a Senate bill does so.
Late last week, Senate aides said, they received word from the House committee with jurisdiction over revenue issues that it would use that constitutional power to block further consideration of the Senate bill.
The problem is stalling efforts to appoint a House-Senate conference committee that would try to reach a compromise on the final form of immigration legislation.
Those negotiations were expected to difficult at best. But unless the procedural stumbling block is resolved, the talks won't even start.
Although the impasse could prove to be a minor problem, it could provide a way for House members who staunchly oppose the Senate's legalization measures to block any compromise efforts. That could mean no overhaul of immigration policy this year.
Senate leaders are trying to determine how to proceed.
Word of the problem was spreading on Capitol Hill on Thursday as President Bush renewed his push for an immigration bill. In a speech in Washington, he stressed that although he recognized the difficulty in crafting a measure, compromise was necessary, particularly in determining how to treat longtime residents who entered the United States illegally.
A week earlier, the Senate passed its wide-ranging bill. The House measure, approved in December, contains no provisions for a guest worker program or for a path to citizenship for illegal immigrants. It would make illegal presence in the country a felony and would intensify border security.
As the Senate edged toward passing its bill, Senate aides received word that Bill Thomas, a California Republican who is chairman of the House Ways and Means Committee, would block it because of its revenue-producing sections.
That practice is known as blue-slipping because Thomas would officially notify the Senate of his intentions on a slip of blue paper.
Thomas did not respond to requests for comment, and committee aides declined to elaborate on the dispute.
The Joint Committee on Taxation and the Congressional Budget Office estimate that provisions in the Senate bill would increase federal revenues by about $66 billion from 2007 to 2016.
The potential for a House objection stemming from those provisions did not come up during senators' lengthy negotiations over their bill this year, a Senate Judiciary Committee aide said.
Last week, Senate Majority Leader Bill Frist, a Tennessee Republican, proposed a technical way of skirting the problem. The Senate's immigration bill could be attached to a House tax bill, Frist aides said.
After legislative maneuvers, the two chambers could separate the tax and immigration measures and try, behind closed doors, to negotiate on a final immigration bill.
The Frist plan faces two hurdles. It cannot take effect without a House vote, which would give the House members opposed to the Senate bill a chance to vote it down.
More immediately, Senate Democrats disagree with Republican assertions that Frist's plan is the only way to go. Minority Leader Harry Reid has refused to approve the plan, preventing Frist from proceeding.
In a sign of the mistrust among leaders in both parties that has characterized much of the immigration debate, Frist spokeswoman Carolyn Weyforth. attributed Reid's stance to a desire to thwart any resolution of the issue until after the November elections.
Many Republicans suspect that Democrats would prefer such a delay so that they can keep criticizing the House's enforcement-only approach.
Nicole Gaouette and James Gerstenzang write for the Los Angeles Times.