The economy is tanking, unemployment is at 8.1 percent and most workers — even some in the White House — are enduring wage freezes this year.

But Congress? When it comes to lawmakers’ paychecks, watch the legislative tangos on the Senate floor this week.

Republican Sen. David Vitter of Louisiana is slated to get a vote — most likely on Tuesday — on a proposal that would force lawmakers to affirmatively vote themselves an annual pay raise, repealing a provision of current law that automatically increases congressional pay each year. Last week, Vitter maneuvered to have his amendment included among a dozen additional GOP proposals to the $410 billion fiscal 2009 omnibus spending bill (HR 1105), which the Senate is considering this week.

The catch-all legislation contains nine leftover spending bills from last year.

The upcoming vote on Vitter’s amendment is problematic for supporters of the underlying spending measure. A vote against the amendment could put a senator in the politically perilous position of defending automatic pay increases for lawmakers at a difficult economic time for nearly all Americans.

If the amendment is adopted, it could prove to be a poison pill, eroding support in both chambers for the yearlong spending measure, and forcing a House-Senate conference.

Additionally, House Speaker Nancy Pelosi , D-Calif., last week threatened to scuttle the omnibus and replace it with a less generous stopgap spending measure for the rest of the year if the Senate makes any changes in the bill.

So on March 6, Majority Leader Harry Reid , D-Nev., introduced a nearly identical stand-alone bill (S 542), a move designed to give political cover to Democrats who oppose Vitter’s amendment and help speed passage of the omnibus.

“We can’t afford to make any changes to this bill because we want to be able to send it to the president,” said a Democratic leadership aide.

Democratic leaders planned to discuss the proposal Tuesday at their weekly policy lunch in a effort to try to assure members that they would be able to endorse the stand-alone bill at a later date.

Vitter said Reid’s approach was “just a diversionary tactic to try to defeat” his amendment.

“He’s going to be pointing to this bill to try to give members cover, knowing that the way to really enact this into law is to pass it as an amendment to a bill that needs to be signed into law,” Vitter said.

Vitter pointed out that Reid agreed to allow a vote on his proposal March 5 only after Vitter threatened to block Reid from canceling a procedural vote on the omnibus. Reid canceled the vote after it became apparent Democrats didn’t have the 60 votes needed to cut off debate on that proposal.