Rep. Jared Polis (Colo.) and three other Democrats filed a discharge petition Wednesday to force a House vote on the Employment Non-Discrimination Act. 

The petition would need to win the backing of 218 lawmakers to force House consideration of the non-discrimination bill passed last year by the Senate. The measure would prohibit employers from discriminating on the basis of sexual orientation or gender identity. 

Discharge petitions are rarely successful, and the petition is likely an attempt to highlight the issue ahead of the midterm elections. A related House bill has a total of 205 co-sponsors, including eight Republicans. 

Along with Polis, who is co-chairman of the LGBT Equality Caucus, Democratic Reps. Rush Holt (N.J.), John GaramendiJohn Raymond GaramendiTrump infrastructure plan gets cold reception House GOP leaders scramble for budget votes Repealing antiquated Jones Act would be a boon to all Americans MORE (Calif.) and Gerry ConnollyGerald (Gerry) Edward ConnollyFlorida students turn to activism in wake of shooting House Dem joins protest at NRA headquarters following Florida school shooting Trump budget threatens local transit projects MORE (Va.) signed the petition. 

House leaders, including Minority Leader Nancy Pelosi (D-Calif.), put their weight behind the effort during a press conference later Wednesday.

"The Senate has passed the ENDA bill in a bipartisan way. The House should take it up," Pelosi said. "Instead of wasting time and money, squandering over three million dollars defending discrimination on the DOMA bill and now squandering more resources to fight equality,  we should be taking up the ENDA bill."

The Human Rights Campaign applauded the petition. The group told The Hill it would be ramping up its advocacy efforts in order to get ENDA through the lower chamber after the election.

“We appreciate the leadership of Leader Pelosi and Congressman Polis in seeking every possible avenue to advance ENDA in the House this year," said David Stacy, the group's government affairs director.

The Senate passed the bill last year with the help of 10 Republicans. However, Speaker John BoehnerJohn Andrew BoehnerRestoring fiscal sanity requires bipartisan courage GOP congressman slams primary rival for Ryan donations Speculation swirls about Kevin McCarthy’s future MORE (R-Ohio) has opposed it, saying it could expose companies to frivolous lawsuits. 

In July, President Obama signed an executive order that would prohibit federal contractors from such discrimination.

The GOP-aligned LGBT rights group American Unity Fund said in a statement it would be continuing to "focus its attention on working with leaders of both parties to identify the 218 votes" the bill needs to pass the House, but criticized the move by Pelosi and others to start a discharge petition.

"House Democrats have decided to use a short-term political maneuver to make a partisan statement on an otherwise strongly bipartisan bill," said Jeff Cook-McCormac, a senior adviser at the organization, noting that ENDA passed the Senate with bipartisan support and now "has more Republican cosponsors than ever before in the House."

A Republican lobbyist familiar with the issue said that the discharge petition could hurt the non-discrimination legislation's chances of being enacted into law.

"Members of the House majority just don't sign discharge petitions, regardless of their position on the underlying issue," the lobbyist said, asking to remain nameless in order to speak freely. "Signing is an explicit act of hostility toward their leadership."

—Megan R. Wilson contributed

This story was updated at 7:30 p.m.