Sen. Orrin Hatch (R-Ut.), pictured alongside Sen. Joseph Lieberman (D-Conn.), after the Senate’s February 2009 vote on the bill.

A day after news broke that legislation granting D.C. a voting seat in the House of Representatives would be re-introduced next week, Sen. Orrin Hatch (R-Ut.) has threatened to filibuster the bill unless changes are made.

According to the Hill, Hatch wants language regarding the additional seat Utah would be granted to be changed from a statewide At-Large seat to a new single congressional district. The legislation, first introduced in 2007, planned to expand the House by two seats — one for the District, another for Utah — until the 2010 congressional re-apportionment. But why Utah? Because its Republican seat would balance out the District’s Democratic one, and because Utah was in line for an additional seat anyhow. In his threat to filibuster, Hatch argued that the decision of what type of seat Utah would get under the legislation should be left to the state, and not written into the legislation.

It was only last year that Hatch helped marshal the votes as a co-sponsor for the legislation, which did successfully pass the Senate. After the February vote, he said, “Participating in the election of those who govern us is at the heart of our American system of self-government. It is a right for which generations of Americans have fought and died to preserve. So I’m pleased with the passage of this historic legislation that will ensure that my home state of Utah and residents of the District of Columbia get the representation in the House that they require and so richly deserve.”

Hatch’s warning puts D.C. Del. Eleanor Holmes Norton and Democratic leaders in a tough position. If they make any changes to the legislation that the Senate passed, which included an amendment overturning the city’s gun laws and preventing it for enacting any new ones, the bill must head to back to the Senate, where Hatch is now saying he’ll filibuster. (It barely avoided a filibuster last time with 61 votes, so the margin on another vote would razor-thin.) This means that Norton, who despises the gun amendment as written but has agreed to accept it in some form for the sake of the larger cause, may not be able to water down the amendment at all, as she’s said she’s still trying to do.

Of course, Norton and the Democratic leadership could acquiesce to Hatch’s demands and make the changes he wants as well, but that would still leave the bill subject to a filibuster from any other senator.

Either way, it’s not going to be a particularly easy path forward for the legislation, which has been stalled since last summer.