The thunderheads loom dark and low as Mike Wiggins Jr. navigates the small motorboat through the shoulder-high grass. “All this,” the Bad River Tribal Chairman says, gesturing at the many acres of wetlands that surround us, “could be ruined if that mine goes in.”

As if on cue, the first low rumble of thunder travels across the water, and a moment later the lightning begins. Wiggins guns the motor, counting seconds between flashes and rumbles. Being on the water during a thunderstorm is one of the few things Wiggins is scared of.

The Gogebic Taconite iron-ore mine is another.

In the heart of northern Wisconsin’s beautiful Penokee Range, two high ridges run parallel to each other 1,200 feet above Lake Superior. The slopes are swathed in hardwood trees, and the valley the ridges form is home to plentiful big game and lined with Class I trout streams — brook, brown, and rainbow. The mineral rights to these 22,000 acres are owned by the mining company Gogebic Taconite (GTAC). Here, outside the sleepy town of Hurley, which literally lies at the intersections of Iron, Copper, Silver, and Granite — the names of some of the town's broad, empty streets — GTAC wants to build what could be the largest open-pit mine in the world, 4.5 miles long and 1.5 miles wide. When finished, the resulting hole would be 1,000 feet deep.

The company says the mine will generate $1.4 billion in tax revenues, a substantial sum in a community where jobs are scarce. But local residents are still divided. Below the range are the wetlands — referred to as Wisconsin's Everglades — that Wiggins fears will be lost to polluting runoff from the mine. They in turn feed into Lake Superior, the repository of roughly 10 percent of the world’s fresh surface water.

In addition to the economic and environmental concerns, the mine project has serious political ramifications. When the Supreme Court's Citizens United decision struck down limits on corporate campaign spending three years ago, corporate donations changed the way elections work in America. In Wisconsin, GTAC and other mining interests spent millions on political donations, resulting in the drastic re-writing of — some would say abolishment of — state mining laws.