Late last week, the United States Senate passed a budget resolution that could grease the skids for the largest sell-off of American public lands in our lifetimes. While the budget has been widely reported as a vehicle for opening up the Arctic National Wildlife Refuge to industrial energy development, its true potential for harm stretches far beyond Alaska.

The new budget rules provide a shortcut for any bill in the Senate Energy and Natural Resources Committee that raises a billion dollars in new revenue to offset proposed tax cuts. The fast-track provision allows for those bills to pass without reaching the 60-vote threshold usually required to end debate in the Senate.

Alaska Senator Lisa Murkowski, chair of the Energy and Natural Resources Committee, has admitted that she is interested in looking beyond the Arctic to raise revenue.

“There are other opportunities for us,” Murkowski told Bloomberg News. “There is a significant way that we can help with the budget process.”

Oklahoma Senator James Inhofe confirmed that Alaska is merely a starting point, adding, “Anything else we can get in there with a simple majority vote we ought to do.”

What could “anything else” include? Selling off national public land could be an appealing target for senators looking to offset proposed tax cuts.

In April 2014, the Congressional Budget Office provided a report on HR 2657, the Disposal of Excess Federal Lands Act of 2013. That report looked at approximately 30,000 of acres of land that were sold between 2000–2011 under the Federal Land Transaction Facilitation Act. Those 30,000 acres brought in more than $100 million in revenue. That same bill was reintroduced several times, most recently as HR 621, which was introduced earlier this year and would require the Interior Department to sell off 3.3 million acres of public land.

The CBO declined to estimate how much money HR 2657 would bring in, because the bill did not provide a time frame for selling off those lands. But extrapolating from the $100 million baseline provided in the report, selling 3.3 million acres of public land could bring in $10 billion or more, making a sale of that size eligible for the fast track rules passed by the Senate last week.

Although the sponsor of HR 621, Rep. Jason Chaffetz, prior to his resignation from Congress withdrew the bill under intense pressure from sportsmen, conservation, and community interests, there is nothing to prevent the Energy and Natural Resources Committee from adding the language of HR 621 to a budget bill, which would then be able to pass the Senate with just 50 votes.

Adding to the risk, the budget resolution avoids a conference committee in which the House could alter the bill — the House is expected to simply adopt the Senate budget without any changes.

New Mexico Senators Tom Udall and Martin Heinrich each proposed amendments to the budget resolution that would have ensured America’s national parks, monuments, forests, and wildlife refuges are not sold off to raise revenues. Neither amendment came up for a vote, which means all American public lands are now at high risk of disposal.

The budget resolution has started a ticking clock. The Senate has given itself until November 13 to pass a tax reform bill; any revenue provisions that come out of the Energy and Natural Resources Committee will have to come up for a vote before then. If a senator decides to pursue a sell-off to meet revenue goals, it could quickly get added to the tax reform bill with almost no debate.

America’s national parks, monuments, and forests have been sacrosanct for over a century. Today, unfortunately, we’re one step closer to seeing “no trespassing” signs all over the lands Americans have hiked, hunted, and fished on for generations.