Advisers to President-elect Donald Trump have reportedly proposed to privatize oil-rich Native American reservations—a particularly polarizing idea in the wake of the protest over the Dakota Access Pipeline. Reuters reports that such reservations likely contain about 20 percent of the nation’s oil and gas, as well as large coal reserves. Rep. Markwayne Mullin (R-OK), who is co-chairing Trump’s Native American Affairs Coalition and a Cherokee tribe member, said: “We should take tribal land away from public treatment. As long as we can do it without unintended consequences, I think we will have broad support around Indian country.” Others see the proposal as inherently problematic. “Our spiritual leaders are opposed to the privatization of our lands, which means the commoditization of the nature, water, air we hold sacred,” said Tom Goldtooth, who runs the Indigenous Environmental Network and is a member of both the Navajo and the Dakota tribes. “Privatization has been the goal since colonization—to strip Native Nations of their sovereignty,” Goldtooth added. But Trump’s advisers, including ex-chief of the Cherokee nation Ross Swimmer, said it’s possible to privatize the reservations while applying limits to any sales outside the Indian community. “It has to be done with an eye toward protecting sovereignty,” he said. According to Reuters, Trump’s transition team did not respond to requests for comment on the idea.