Legislation to protect 400,000 acres of Colorado land – including three fourteeners – advanced in the U.S. House on Wednesday, despite not having support from the Colorado Republican whose district is home to a majority of that land.

The House Natural Resources Committee voted 23-15 in favor of the Colorado Outdoor Recreation and Economy Act, or CORE Act. The bill now goes to the full House for a vote.

In the committee, the bill divided Coloradans along party lines. It is sponsored by Rep. Joe Neguse, a Lafayette Democrat, and cosponsored by Rep. Diana DeGette, D-Denver, but was opposed by Rep. Doug Lamborn, a Colorado Springs Republican.

Lamborn raised concerns on behalf of a Colorado colleague: Rep. Scott Tipton, the Cortez Republican who represents much of the area covered by the CORE Act and does not support it.

“We should have deference to the 3rd Congressional District and to not have it, I think, is another fatal flaw in this bill,” Lamborn said of Tipton’s district. “Let’s look for opportunities to help Colorado and the entire West have good recreation in the future, but this bill does not accomplish it.”

The CORE Act would preserve Continental Divide land in the White River National Forest, designate more of the San Juan Mountains as wilderness and safeguard about 200,000 acres in the Thompson Divide from oil and gas leases, the most controversial provision in the bill.

If passed, it would be the largest Colorado public lands law in a generation.

“Our public lands in Colorado really define who we are as a state,” Neguse said. “Folks in Colorado understand that getting outside doesn’t only improve our health but contributes to a higher quality of life and a booming economy that supports $9.7 billion in wages across the state.”

Rep. John Curtis, a Utah Republican, said about 65 percent of the land that would be affected is in Tipton’s large western Colorado district. Without Tipton’s support, “the probability of this thing getting through the Senate and into law, signed by the president, is near zero,” Curtis said.

Tipton’s office says it was told about the CORE Act only a couple hours before it was introduced. While there have been conversations between the offices of Tipton and Neguse, Tipton’s office says it was not consulted on amendments to the CORE Act and none of the recommended changes the two offices discussed were included in a Neguse amendment to the bill.

A spokesman for Tipton said he doesn’t support the bill but has been willing to work on some sections of it with Neguse. Tipton cannot support the Thompson Divide portion of the bill “until there is consensus among all impacted counties on permanent mineral withdrawal.” He also has concerns about the bill’s effects on a military training site in Gypsum, the spokesman said.

In an interview after Wednesday’s committee vote, Neguse said he is an eternal optimist who is always willing to work with others on legislation and will continue doing so. He strongly disagrees with Curtis’ claim that the bill cannot become law without Tipton’s backing.

“This is a bill that has broad support from a lot of community leaders,” Neguse said. “County governments, city governments, the business community back in Colorado. …I am hopeful that the bill will make it through the House, have a fair hearing in the Senate and attract support in Congress as it makes its way through.”

A Senate version of the bill is being sponsored by Sen. Michael Bennet, a Denver Democrat. The state’s other senator, Cory Gardner, a Yuma Republican, is not cosponsoring the bill. A Gardner spokesperson said he has worked to preserve public lands by instead sponsoring different legislation and trying to fully fund the Land and Water Conservation Fund.