The late Sen. Ted Kennedy, whose bona fides as a Democrat and supporter of environmental issues was unrivaled, was nonetheless an entrenched opponent of the Cape Wind proposal. His nephew, Robert F. Kennedy Jr. — himself an environmental attorney and activist and founder of the watershed protection group Waterkeeper Alliance — has argued relentlessly against the project, including in prominent op-eds in The New York Times and, more recently, The Wall Street Journal.

But the chief underwriter of the campaign to stop Cape Wind, which includes major funding for Parker's alliance, is William Koch, scion of the founders of the oil refining giant Koch Industries, chairman of the gas and coal supplier Oxbow Corp. — and owner of a sizable estate in Osterville, Mass., just west of Craigville beach.

From a recent compilation prepared by the environmental group, The Sierra Club:

While the Alliance is largely a local group, concerned about the possible environmental, aesthetic, and economic impacts of the wind farm, their efforts have been sustained almost entirely by Mr. Koch and his gas and coal conglomerate, Oxbow Corp. In a 2006 interview with Forbes, Mr. Koch admitted spending $1.5 million on the Alliance. The group's 2011 annual report form filed in Massachusetts includes Mr. Koch as a co-chairman for the organization — despite his Palm Beach, Florida, address, thousands of miles from Nantucket Sound. The Alliance's 2009 ... IRS form indicates that Mr. Koch also paid most of president Audra Parker's $147,499 salary.

Koch has made no mystery of his opposition to Cape Wind, and Parker is unfazed when asked about his involvement in the alliance, describing it as a red herring that distracts from what she says are thousands of grassroots supporters.

"Bill Koch is our biggest donor, over time he's been our biggest donor," Parker conceded, adding that he accounts for about 20 percent of the group's operating budget, with smaller donors representing the rest. "Yes, our largest donors are funding the bulk of it, yes — but that's typical. Obviously you're going to have a few $100,000 donors and a lot of small donors, so you just do the math. But it's pretty typical of a nonprofit," she said. "Koch has property here, so he cares about the area just like everyone else. It has nothing to do with oil and gas interests. I really don't think his business model is threatened by Cape Wind."

To further demonstrate her point, Parker digs into a file folder and produces letters from a variety of supporters and small donors to the alliance. "I'm elderly and I have a limited income, but I gladly offer this small amount because I do not want to leave this earth with the Sound desecrated," reads one letter, which accompanies a $15 donation. A $25 donor writes: "You will never know how much we appreciate all that Save Our Sound has done to protect our sound. Thank you, thank you, thank you."

Parker, who spent summers on the cape growing up and who now lives in the area full time, begins reading aloud another letter, sent in 2011, after Interior Secretary Ken Salazar issued a final federal approval of the project.

"Thank you so much for all you folks are doing to save one of the most beautiful pieces of water in the world," she begins. "When the news came down the other day, I was devastated. Frankly, I took it much harder than expected. It is unfathomable to me that a group of investors can simply swoop in and lay claim to a national treasure. This is the greatest theft in Massachusetts history. Cape Wind has devastated not only the..."

And then Parker tears up and stops.

"I can't even read this," she said. "It always gets to me."

One of many letters sent to the Alliance in support of its efforts to stop Cape Wind from being built. (Photo by Tom Zeller Jr.)

The truth behind the finer points of the long-running Cape Wind dispute are, as one might expect, a matter of vigorous debate. For every poll or study commissioned or endorsed by the alliance that shows Massachusetts residents oppose the project, that property values will drop, or that electricity rates will skyrocket, supporters can point to countervailing analyses that show quite the opposite.

A 2010 study of regional electricity markets, for example, suggested that Cape Wind would actually work to lower wholesale electricity prices in New England over time.

The Obama administration also has made it a high priority to encourage the diversification of the nation's energy portfolio through generous subsidies for the burgeoning clean energy sector, and Massachusetts, like many states, now requires local utilities to obtain a certain percentage of their electricity from renewable sources — which means that new clean energy facilities must, at some point, be built.

And while it is virtually certain that the turbines will have implications for local bird life, fish populations, boat captains and plane pilots, thousands of pages of state and federal agency analysis, judicial review and subsequent re-analysis have suggested that, all things considered, the project's virtues outweigh its impacts.