HELENA — An Oklahoma senator who last week blocked passage of a bill protecting the North Fork of the Flathead River from energy development says he would consider an amended bill, such as halting development for 20 years rather than forever.

Sen. Tom Coburn, R-Okla., also said Congress could transfer the land to Montana and allow it to withdraw the land from development — but that would reduce the state’s share of federal “payments in lieu of taxes” to local governments.

“If Montana wishes to have provenance over the land-use decisions in the North Fork watershed, then they should also assume financial and management responsibility from the American taxpayer,” he wrote.

Coburn is one of three GOP senators — Ted Cruz of Texas and Pat Toomey of Pennsylvania are the others — who objected last Thursday to passage of the North Fork Watershed Protection Act, defeating a “unanimous consent” vote.

The legislation essentially would protect national forest lands from oil, gas and mineral extraction but allow continued forest management in the North Fork Flathead River drainage. It is similar and reciprocal to action taken by the British Columbia provincial government in the Canadian North Fork.

U.S. Sen. John Walsh, D-Mont., tried to gain the consent, which, if successful, would have sent the measure to President Barack Obama for his signature.

The bill, which has bipartisan support from Montana’s delegation, would withdraw 362,000 acres of federal land from energy development in the North Fork watershed just west of Glacier National Park.

Cruz and Toomey ignored inquiries about why they blocked the measure. But Coburn provided a copy of a letter he wrote Friday to Senate Minority Leader Mitch McConnell, R-Ky., explaining his reasons and continuing his objection.

Coburn said the bill forever blocks any energy development on the land, regardless of technological innovations that could create cleaner extraction methods. “It is doubtful that Congress has the foresight to determine our nation’s energy needs or natural resource-development capabilities a decade from now, let alone forever,” he wrote.

He suggested putting a 20-year “sunset” on the federal land withdrawal, after which Congress could consider whether to extend it.

Walsh’s office dismissed Coburn’s rationale as “rooted in politics — not policy.”

“This bill is important for Montana’s lucrative outdoor economy and it protects Montana’s clean air and water,” Walsh spokeswoman Andrea Helling said. “The (Republican) senators should end their partisanship and vote for this bipartisan bill that would truly create jobs and benefit our economy.”

When asked why the Democratic leadership didn’t bring the bill to the Senate floor for a regular vote, Walsh’s office said the Senate calendar is too crowded for a lengthy debate, which would be avoided with the unanimous consent vote.

Bringing the bill to the floor now would take 60 votes, and would require many hours of debate, his office said.

Coburn said if sponsors of the North Fork bill aren’t willing to amend it, he’d like “the opportunity to offer amendments to address at least some of my concerns.”