Nine U.S. Senators plan to introduce a bill mandating that Washington, D.C., residents vote on whether to keep the city's marriage equality law.

According to the DC Agenda newspaper, the National Organization for Marriage is a proponent of the bill and announced the senators' plans on Tuesday.

Republican senators Robert Bennett of Utah, Jim Bunning of Kentucky, John Cornyn of Texas, Mike Enzi of Wyoming, James Inhofe of Oklahoma, Pat Roberts of Kansas, David Vitter of Louisiana, and Roger Wicker of Mississippi are backing the bill.

Their bill, the companion to the House version introduced by Utah representative Jason Chaffetz, is being introduced during the period of congressional review for the D.C. ordinance, which ends in March. Chaffetz's bill only has one cosponsor, Ohio representative Jim Jordan, according to the DC Agenda.