Robin and Linda Williams at their Shenandoah Valley home. The duo, made famous by “A Prairie Home Companion,” wrote a song protesting the proposed Atlantic Coast Pipeline, the original path of which ran past their back yard. (Charles Ommanney/The Washington Post)

The first hint that something’s afoot at the Shenandoah Valley frame house with its put-up-your-feet-and-stay-awhile porch furniture is on the front lawn.

It’s a small white sign, planted beside the road and across from the lowing cows, in grass that’s preternaturally green from this summer of unusual rains. And it shows a big red circular “no” symbol slashing through the word “pipeline.”

Then the genial Robin Williams, one-half of the Robin and Linda Williams country-folk duo made famous by the “Prairie Home Companion” radio show, puts down his cup of tea, pulls out his iPhone and starts playing a YouTube video. It’s a recording of the couple strumming away on banjo and guitar right here in their own front yard in Middlebrook, Va., and intoning in their wistfully catchy, singalong way:

We don’t want your pipeline, we don’t want your pipeline,

We’ll take the sunshine, the water and wind!

We’re gonna put a stop sign on Dominion’s pipeline.

Go tell your neighbors! Go tell your friends!

It’s a protest song — anti-fracking propaganda in the old-time musical vernacular of the Appalachian mountains! The toe-tapping soundtrack to Virginia’s own Keystone-style controversy! The Williamses played it to an appreciative crowd at the recent Music for the Mountains Festival, and it has become the call to arms at many an anti-pipeline meeting.

The pipeline Robin and Linda Williams don’t want is a true behemoth, the 42-inch diameter lower bowel of West Virginia’s fracking wells. Known as the Atlantic Coast Pipeline, it’s designed to carry up to 1.5 billion cubic feet per day of methane (that’s Marcellus shale gas in the biz) for more than 500 miles through the Shenandoah Valley, across the Blue Ridge Mountains and over the Piedmont and then the Tidewater to North Carolina, burrowing its way through both public and private lands.

A little more than a year ago, when the Williamses first learned about this joint project of energy giant Dominion Resources and three other regional companies (A letter in the mail says Dominion’s coming through/And they want us to think there’s nothing we can do), the pipeline’s proposed route ran right past their back yard.

Now, NIMBY is not the first acronym that comes to mind when you meet the laid-back Williamses. But the prospect of fracked gas flowing by this eight-acre homestead with its abundance of fresh summer vegetables left them a little hot under the collar. They began talking with friends and neighbors, and, this being rural Virginia, a few miles outside Staunton, with its chichi restaurants and American Shakespeare Center, they have friends and neighbors of every political stripe. Who, it turned out, objected to the pipeline from every conceivable political angle.

“The environmentalists don’t like fracking,” Robin says. “They want to see money spent on renewables.”

As for local landowners, “Dominion was going to come on land and survey it without permission,” Linda says, and that didn’t sit well with them.

With both ends of the political spectrum “all riled up,” the Williamses decided to enhance the community efforts not by lobbying or filing lawsuits but by writing lyrics — ones that address the concerns of liberals and libertarians alike.

Think Pete Seeger’s antiwar activism gone green.

The Williamses have joined friends and neighbors concerned about the environment and property rights. (Charles Ommanney/The Washington Post)

They’ll bring cough and corruption like we’ve never seen

Gouging our Forest, our mountains and our streams.

Five hundred miles long and fifty yards wide

Blasting through our homes with their pipeline

The proposed route, which no longer cuts quite as close to the Williamses’ property, will require clear-cutting swaths of farmland and wild flora. It takes the pipeline right through the National Forest, “where it’s illegal to move a rock or pick a flower,” Linda says. “But the governments will let a corporation come through!” Robin adds.

Now sinkholes, explosions and gas-line leaks,

You hear it on the news almost every week.

Dominion says ‘Don’t worry,’ but it ain’t wise

To be flirting with disaster with their pipeline

Who knew? The rock formation in the region, known as karst, is characterized by caves and underground drainage channels, making it prone to sinkholes. “One opened in the barn of a farmer down the road,” Robin says. And the gas-line leaks? “That doesn’t affect you until it affects you,” Robin says. “But it can happen anywhere.”

These Richmond operators don’t care ’bout you and me.

They just want to make a killing when they got more than they need.

And you can bet they’re safe in their houses so fine,

Far, far away from the pipeline

The Williamses say it took time to come up with the right noun: “Operators,” they figured, worked for both politicians and energy company honchos. But much of the indignation in this verse is aimed at Virginia’s Democratic governor. Terry McAuliffe, Linda says, “ran as a green candidate.” That, she now says, is “hooey.”

Now these Big Boys say, ‘It’s a done deal.’

But nothing’s done as long as we’ll

Stand together for our rights and our property

And keep pushing back against their pipeline

Here’s the rallying cry for the traditional anti-corporate, pro-property-rights values of rural Virginia. You begin to understand the don’t-tread-on-me line of thinking, Linda explains, when you’ve poured “heart and soul” into a 19th-century white frame house that’s been under constant renovation since you moved in nearly 40 years ago.

The pipeline’s proposed route goes through these pastures near the Williamses’ home. (Charles Ommanney/The Washington Post)

The anti-pipeline coalition is “an unlikely alliance,” says Linda, who was seen parading through Staunton on Independence Day beside a float labeled, “Property rights are patriotic.” Not the slogan you would necessarily associate with a darling of NPR. But the thing that’s been great about this coalition, Linda says, is that it “opens people’s eyes” to other ways of seeing things: The enviros have picked up on the anti-authoritarian tradition, she says, and some of the tea partyers have wondered whether government couldn’t perhaps help out. A whole new kind of anti-pipeline political harmony!

The energy group has published its own pro-pipeline propaganda, of course. The pipeline will increase “the reliability and security” of natural gas supplies, it says, “creating new jobs, maintaining cleaner air, and providing lower prices to heat and power homes and businesses.” But it’s not exactly hum-along reading.

A spokesman for Dominion explains that if everything stays on schedule, the company could get approval for the project next summer, start construction later that year and go into operation before the end of 2018.

About 300 landowners have objected, he says; 52 changed their minds after getting a follow-up call; and the pipeline company has so far filed 58 lawsuits. There is a state law about surveying private property, the spokesman says, and “as long as we follow the statute, by law we don’t have to ask for permission.” He’s also aware of at least two lawsuits that landowners have filed, alleging that the state statute violates the U.S. Constitution.

But the company has no plans to sway the court of public opinion with lyrics of its own. Which could be a mistake. Because whatever you feel about fracking, the Williamses’ tune, with its tree-huggin’, tea-party-pleasin’ lyrics, is almost impossibly hard to forget. You find it jingling around in your head at the darndest moment, when you’re adjusting the A/C or pumping gas.

And it has apparently already found a following in the energy business.

A few months ago, the Williamses received an e-mail from a natural-gas trader in Houston describing how he sits on an open trading floor with about 50 other people.

“I’m not saying we agree, or disagree, with your stance on the pipeline,” the e-mail says. “However, I did want you to know we (our natural gas trading team) often whistle, sing or play your YouTube video with the Pipeline Song.”