A copper mine that could provide hundreds of high-paying jobs on the Iron Range also is threatening to crack the fragile alliance of blue-collar Democrats up north and the environmentalists that are an influential part of Minnesota DFL’s base.

Iron Range Democrats are looking to the proposed PolyMet copper-nickel mine as a way to rejuvenate an area rocked by years of declining mining employment. But such mines also have a long history of pollution in other states and countries, and some have warned that a mine expected to last 20 years could result in centuries of cleanup.

All sides are closely watching as Gov. Mark Dayton’s administration faces a crucial decision on the project that could come near the election.

At risk is a political coalition that has made good on a string of high-profile DFL priorities like same-sex marriage, higher taxes for the rich and expanded union influence around the state. Dayton is depending on that same coalition to help him press for a second term and keep the state House in DFL hands.

“We are going to go through some hard times,” predicted Rep. Tom Anzelc, DFL-Balsam Township. “This may be the signature event in the decades-long battle between jobs and the preservation of the environment. This battle determines what kind of a Minnesota Minnesotans want.”

Democrats are scrambling to contain the conflict and prevent another “massacre” of 1978, when Republicans capitalized on similar outrage over the creation of the Boundary Waters Canoe Area Wilderness. Rivals divided the DFL over the issue and allowed Republicans to make historic electoral gains, claiming the governor’s office and both U.S. Senate seats.

Already some Republicans are seizing on the rare opening, after years mired in scandal and defeat.

Former House Speaker Kurt Zellers is banking on his support for mining to help him emerge as a breakout Republican candidate for governor. He released a graphic on social media last week with text over a scenic lakeside landscape: “Fact: We can open copper and nickel mines while safeguarding natural resources with the toughest environmental standards already in place.”

Zellers, who represents the area around Maple Grove, has already gone deep into DFL territory in northern Minnesota to make his pitch: “I think it is our North Dakota oil fields,” he said. “It’s a no-brainer. Am I the only guy, Democrat or Republican, talking about it? Yeah, absolutely. There are a vast majority of Minnesotans that don’t believe the hysteria that this is going to ruin the Boundary Waters.”

PolyMet Mining Corp. says it will invest $650 million initially, create up to 360 high-paying mining jobs and infuse another $500 million annually over the projected 20-year life of the mine.

There also is the possibility of touching off a dramatic mining renaissance in the area. Other companies are already lining up to tap one of the world’s largest untouched deposits of copper, nickel and other precious metals needed for products ranging from smartphones to hybrid cars.

But with that comes the potential for acid drainage that could require centuries of special cleanup and jeopardize the watershed that feeds Lake Superior.

How much PolyMet must pay to treat the water — and for how long — has emerged as a key friction point in the project. Future taxpayers could face a stiff bill for cleanup if PolyMet is not required to kick in enough money.

So far, the Democratic governor has offered little hint of how he is leaning. Dayton has built a political foundation from his strong pro-jobs reputation on the Iron Range, but he faces intense pressure from well-funded environmental groups and his former wife, Alida Messinger, a top DFL donor and avid conservationist.

Governor taking his time

Dayton said he has just begun reviewing a recently released 2,200 page environmental review. “I am going to wait until all of the facts are known before I come to a conclusion,” he said in an interview with the Star Tribune. “It’s hugely important and there are very strong feelings on both sides.”

Some Democrats already are diving in — and occasionally taking a beating for it.

State Auditor Rebecca Otto traveled to Democratic strongholds on the Iron Range in recent weeks, holding a series of meetings to express her deep skepticism about the future of copper and nickel mining in Minnesota.

The DFLer told crowds that copper mining operations have a history of shutting down and leaving taxpayers to shoulder the cleanup costs.

Even the best experts have no idea what cleanup costs would be over the course of hundreds of years, Otto said. “If we think we do,” she said, “we are kidding ourselves.”

Suddenly, the auditor who was little known on the Iron Range became a household name after taking a barrage of criticism from local mining supporters. Her campaign also released a fundraising letter outing her lone vote against 31 mineral leases on the Iron Range — leases that are routinely approved by the governor and other state leaders.

That infuriated mining supporters. A DumpOtto.com website popped up, lambasting Otto for owning a hybrid car and wind turbine and then coming out against mining for the very materials needed to make those products.

“I find it a little smarmy,” Anzelc said of his fellow DFLer’s fundraising push.

Otto did not back down.

“It’s not a secret that people who run for elected office fundraise,” she said. “The issue of the day is the financial assurance. I am doing my job, and I am not going to stop. … We need to go into this with eyes wide open.”

The mother lode

Legislators from the Iron Range say the minerals sitting underground are essential to meeting consumer demand, whether they come from Minnesota or Africa. In Minnesota, they note, the regulations are strong and the workers eager.

“They are hitting the mother lode on every single drill hole,” state Sen. David Tomassoni said of the mineral exploration. “Your little cellphone has something like 39 minerals in it and not one of them fell out of the sky.”

In his office at the Capitol, a large, blue PolyMet poster leans against the Chisholm DFLer’s desk. It features a drawing of a huge dump truck and windmills in the background. The sign reads: “Jobs AND Environment.”

If environmental regulations snuff out the state’s mining industry, “There is nothing else,” Tomassoni said. “We become a ghost town.”

State leaders are poring over the environmental review against an increasingly uncertain political backdrop.

“It’s very intense,” said Craig Grau, former political science professor at the University of Minnesota Duluth. “As often happens politically, you have immediate rewards versus long-term losses. That’s a difficult thing to balance.”

House Speaker Paul Thissen is trying to thread his way through the perilous political landscape. He and other Democrats say the differing factions within the DFL have learned to stick together even as they untangle politically complex topics, such as the marriage issue.

He is holding out hope a deal can be reached that both sides can live with.

“We are pretty good at working through divisive issues and coming up with something,” said Thissen, DFL-Minneapolis. “This will undoubtedly be a challenge, but we will be OK if we continue to talk it through and focus on the facts.”