Senate Democrats are expected to throw themselves into defeating a resolution to roll back the Environmental Protection Agency’s authority to regulate greenhouse gases on Thursday.

Democratic Sens. Jeff Merkley (Ore.) and Tom Udall (N.M.) will hold a news conference with former EPA Administrator Russell Train to protest the measure, which automakers argue would have the adverse effect of reversing an agreement on national fuel economy standards.

The joint resolution authored by Sen. Lisa Murkowski (R-Alaska) has 41 co-sponsors, and Sen. Jay Rockefeller (D-W.Va.) recently expressed his support.

Still, Murkowski acknowledged the difficult climb to reach the 51 votes needed to pass the resolution when it comes before the Senate on Thursday.

“I think we recognize the very high hurdle … of the likelihood of this getting signed into law. It’s a very high bar to meet,” Murkowski told reporters Wednesday. She added that she thinks it’s important that lawmakers still “make a statement” on the issue.

President Barack Obama threatened on Tuesday to veto the resolution if it clears both chambers.

Murkowski’s resolution comes to the floor as Senators on both sides scurry to address the broader issue of energy reform, which has taken center stage in the wake of an ongoing oil leak in the Gulf of Mexico. Majority Leader Harry Reid (D-Nev.) is scheduled to meet with pertinent committee chairmen Thursday to map out a strategy on energy reform, which could include pushing legislation approved by the Energy and Natural Resources Committee last year.

Murkowski, ranking member of the Energy panel and a co-author of the bill with Chairman Jeff Bingaman (D-N.M.), told reporters Wednesday that she was “pleased that finally it’s on the radar.” But she highlighted her surprise that the bipartisan legislation was not considered an attractive option earlier in the debate, when Democrats struggled to find legislation that could win enough support on the floor. Sens. John Kerry (D-Mass.) and Joe Lieberman (ID-Conn.) have also been working on their own legislation.

“It’s like this energy bill that went through the committee, three months of markup over 100 amendments … never gets a mention, despite the substance and a real merit of the bill,” Murkowski said.