WASHINGTON – A coalition of House and Senate Democrats will soon introduce legislation designed to roll back the "Defense of Marriage Act" that outlaws same sex marriage. Though unlikely to pass the GOP-controlled House, the measure would highlight the political distance between Democrats and Republicans on this divisive issue.

The "Respect for Marriage Act" will be introduced in the House Wednesday by Judiciary Committee Ranking Member John Conyers (D-MI) and Reps. Jerrold Nadler (D-NY), Barney Frank (D-MA), Tammy Baldwin (D-WI), Jared Polis (D-CO), David Cicilline (D-RI) and 105 co-sponsors.

The "key civil rights legislation," as the Democrats called it in an advisory, would "repeal DOMA in its entirety." Fretting that the 1996 law "singles out legally married gay and lesbian couples for discriminatory treatment under federal law," they plan to announce its introduction Wednesday at a press conference, alongside LGBT-rights advocates and two of the lead plaintiffs in challenges to the law.

A companion bill is expected to be introduced in the upper chamber by Sens. Dianne Feinstein (D-CA), Patrick Leahy (D-VT) and Kirsten Gillibrand (D-NY).

Even same sex marriage advocates privately concede that the measure won't pass Congress, but they're hopeful it will highlight the significant shift in public opinion for the issue and put Republicans on the defensive.

The Obama administration announced last month that it would no longer defend parts of DOMA, declaring it "discriminatory" and unconstitutional. "I stand by my long-standing commitment to work with Congress to repeal the so-called Defense of Marriage Act," President Obama said. "It's discriminatory, it interferes with states’ rights, and it’s time we overturned it."

In response, Speaker John Boehner (R-OH) pledged to use the House's resources to continue defending the law.

Maggie Gallagher, chairman of the National Organization for Marriage, dismissed repeal as a fool's errand.

"We're pretty confident that Pres. Obama has zero chance of repealing DOMA, which is why he's chosen an end run around the democratic process," Gallagher told Raw Story in an e-mail.

Michael Cole-Schwartz, a spokesman for the Human Rights Campaign, championed the effort.

"DOMA sets out to specifically disadvantage certain kinds of families and with five states and DC granting marriage licenses to same-sex couples, it's time the federal government stop playing favorites and instead create an equal playing field for all Americans," Cole-Schwartz told Raw Story.

Repeal of DOMA would also lift a tremendous burden on Americans with same sex partners from other countries. Federal law prohibits recognizing unmarried unions for immigration purposes, forcing many same sex couples to live apart.

"The end of DOMA will mean the beginning of a new life for Americans with partners from abroad," said Steve Ralls of Immigration Equality, adding that his group is "committed to supporting its repeal, both through Congressional action and through constitutional challenges."