Another Senator has thrown his support behind a measure that would prohibit workplace discrimination based on sexual orientation or gender identity.

Sen. Bill Nelson (D-FL) said Monday that he’s decided to co-sponsor the Employment Non-Discrimination Act, after months of lobbying and public pressure.

The bill has now been co-sponsored by 54 senators, including Republican Sens. Susan Collins (R-ME) and Mark Kirk (R-IL), and is expected to gain another sponsor once Sen.-elect Cory Booker (D-NJ) is sworn in Friday.

Nelson’s name was listed Monday among the bill’s sponsors on a Library of Congress website that monitors legislation, which came the same day as Senate Majority Leader Harry Reid’s (D-NV) announcement that the Senate vote on ENDA would come before Thanksgiving.

Only two Democrats, Sens. Joe Manchin (D-WV) and Mark Pryor (D-AR), have not yet co-sponsored the legislation, although two Republican senators, Orrin Hatch (R-UT) and Lisa Murkowski (R-AK), voted for the bill in July in committee.

Their votes, along with Booker's, would leave the measure just three votes short of the 60 votes it needs to clear the Senate.

Roll Call reports that a coalition of gay rights and civil rights groups and labor organizations are lobbying six Republican senators in hopes of attracting their vote on the legislation, which is similar to a bill that gained support from eight Republicans – none of whom remain in the Senate – 17 years ago and failed by a single vote.

[Image via Agence France-Presse]