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WASHINGTON, D.C. - The House of Representatives may introduce its version of the Violence Against Women Act this week, as Congress attempts to reauthorize an 18-year-old law designed to strengthen legal protections against victims of domestic violence.

But prospects for the attempt to combine House Republican proposals for the law with the version passed by the Senate in April remain unclear as the year-end deadline draws near.

The two bills are relatively similar, with the exception of three additions favored on the Senate side: expanded protections for the gay community, undocumented immigrants, and Native American women. Today Democratic women in the Senate said a House bill would be dead on arrival without those aspects.

"A bill like that is an absolute non starter in the Senate," said Sen. Patty Murray of Washington, pointing out their version passed with a strongly bipartisan 68-31 votes last spring.

Murray and her colleagues appealed to female members of the House GOP at a press conference this morning. Sen. Kay Hagan of North Carolina was more blunt in her remarks.

"A 911 operator doesn't take that call and ask, 'Who is that on this on the other end of the line? Are you an immigrant? Are you gay? Are you on an Indian reservation? They respond to that call like everyone expects them to do," she said.

Under current law, undocumented immigrants who are victims of domestic violence can be given a temporary visa, partly as incentive to come forward to authorities. The House bill denies a Democratic attempt to raise the cap on the number of visas available for the program, and removes a standing ability for that victim to apply for permanent residency after three years.

Meanwhile, Native American women on Indian reservations are currently exempt from the law due to jurisdictional boundaries between state, federal, and tribal governments. The Senate bill would allow non-native perpetrators of abuse on those women to be tried in tribal courts if living on tribal land.

According to the U.S. Census, 50 percent of Native American married women are in relationships with non-Indian men.

Opponents of the Senate bill also cite duplicate programs and failure to expand protections against potential fraud as reason for concern, in addition to expanding costs. The Congressional Budget Office reports the Violence Against Women Act costs taxpayers $660 million annually to support.

Negotiations are being spearheaded by House Majority Leader Eric Cantor and Vice President Biden, who was involved with the original bill's introduction in 1994, when he was a senator. But while most of the political rhetoric in Washington lately has been directed at the "fiscal cliff," both parties have been relatively silent on this matter - a possible testament to how serious each side is about reaching an agreement.

Last week, 10 House Republicans signed a letter to that chamber's leadership urging passage of a bill "similar to that which has already passed the Senate." The letter was sponsored by Democratic Rep. Gwen Moore of Wisconsin, and was signed overwhelmingly by members of that party.