Staffers for Senate Majority Leader Harry Reid are circulating a bill to legalize poker playing on the Internet that's backed by large casino interests.

The Nevada casino companies pushing the measure were among the Democrat's biggest donors during his fierce re-election fight. They argue the bill would provide consumer protection for poker players and would provide some tax revenue for federal and state governments.

On Wednesday, three Republican lawmakers sent a letter to Mr. Reid and Minority Leader Mitch McConnell (R., Ky.) opposing any efforts to pass Internet poker legislation during the lame-duck session.

"Congress should not take advantage of the young, the weak and the vulnerable in the name of new revenues to cover more government spending," Rep. Spencer Bachus (R., Ala.), the ranking Republican member of the House Financial Services Committee and others wrote.

Jim Manley, a spokesman for Mr. Reid, declined to comment.