VINEYARD HAVEN, Mass. — The artfully lettered sign on North Road (“WELCOME BACK FIRST FAMILY”) is a rare tangible token of the return of Barack Obama to Martha’s Vineyard. After seven Obama presidential vacations here, Vineyard residents — and regular summer visitors — are entitled to feel blasé.

Passing the welcome-back-Obamas sign Saturday reminded me of a painted board nailed to a tree in 1998 reading, “HOO RAH FOR BILL.” That Vineyard statement of support for a vacationing Bill Clinton — then caught up in the White House intern sex scandal — endured as a tattered remnant of the impeachment saga well into Obama’s first term.

Not only did the Clintons spend six presidential summers here, but the island was also central to Hillary’s political career. The Democratic nominee will attend a fundraiser on August 20 at the waterfront home of Frank and Carol Biondi in Edgartown. There should be a plaque on the house since the Biondis also hosted the kick-off fundraiser of Hillary’s nascent Senate campaign in August 1999. That may have been the first political event in modern history that an incumbent president attended but remained silent on the sidelines beaming.

If Hillary is victorious in November, the POTUS tradition of Vineyard vacations is likely to endure, although the Hamptons could beckon. What is virtually certain is that Hillary will not repeat Bill’s two poll-driven rustic retreats to Jackson Hole, Wyoming, since anecdotal evidence suggests that the former first lady is not enraptured by the joys of camping out under the stars.

[Hillary Clinton and the Dream No Longer Deferred]

Bill Clinton came from Arkansas and Obama from Chicago, so the gravitational pull of this island seven miles from Cape Cod was not rooted in memories of childhood or family heritage. So why has Martha’s Vineyard become the Permanent Democratic Summer White House?

There are obvious answers: The natural beauty; Oak Bluff’s proud history as a black vacation refuge; four golf courses (Obama played Sunday); the presence of Democratic patriarch Vernon Jordan and Obama friend Valerie Jarrett; a sprinkling of Hollywood; an overwhelming Democratic electorate; and the Secret Service’s comfort with a secluded spot that can only be reached by boat or plane.

But, after two decades as a regular summer renter, I feel that these are only partial explanations. More than any other gilded destination, Martha’s Vineyard speaks to something deep and abiding in the Democratic worldview.

Even though the Vineyard’s summer population swells to more than 100,000 (compared to 16,000 year round), the island is miraculously free from every taint of mass-market consumer culture. Missing are the golden arches and every other fast-food chain restaurant. There are no shopping malls or even downsized versions of Walmart and Home Depot. Even Whole Foods has not made it across Vineyard Sound.

Driving around the island (all major roads are two lanes) or surveying the agriculture vote at the West Tisbury farmer’s market, it is easy to get the impression that the dominant industries are the sale of cut flowers and freshly baked pies.

[Popular Obama to Sit Out General Election’s Early Innings] 

The Vineyard — unlike, say, the Bush ancestral watering hole in Kennebunkport, Maine — boasts a fabled literary tradition. While titans like Bill Styron have died (his widow, the poet Rose Styron, remains a major Vineyard fixture), the torch is carried by such novelists as the sublime craftsman Ward Just and Pulitzer-Prize winner Geraldine Brooks — who are both year-round residents.

Over the two decades of presidential summers, the Vineyard has increasingly become a refuge for the mega-rich. A single half page of real-estate listings in the current issue of the Vineyard Gazette lists three properties selling for more than $10 million and a fourth that is snootily described as “Exclusively Priced.”

But part of the magic of the Vineyard is that these temples to hedge-fund hubris and Wall Street wealth are hidden from view down circuitous and often mile-long dirt roads. This is discreet excess rather than gold-plated, Trumpian in-your-face triumphalism. The wealthy drive Ranger Rovers not Bentleys — and leave their haute couture dresses and bespoke suits at home.

The Vineyard represents small-town life (no one locks their doors) shorn of anything that might jostle liberal sensitivities. Republicans tend to be of the old-line patrician variety, even though (ssshhh) Donald Trump carried each of the six towns on the island in the Massachusetts primary.

This is an island for bird watching rather than duck hunting. The surrounding waters are dotted with white sails in the sunset, but mercifully free from the roar of jet-skis and power boats. While year-round residents are rightly enraged by the shrinking supply of affordable housing, the biggest problem for summer visitors is getting ferry reservations for their cars.

For an anthropologist eager to study liberal well-to-do Democrats in their natural ideological habitat, there is no better place than Martha’s Vineyard during a presidential summer vacation. And if certain things like a Big Mac are missing, that too represents something important about the liberal psyche.