On Tuesday, as visitors to the island disembarked the ferry in Oak Bluffs for the Fourth of July holiday, a spit of a beach nearby was already full of sunbathers. Some people sought relief from the 83-degree heat (and an unwanted touch of humidity) in waist-deep water.
One couple sitting on a bench as they watched the ferry come in said the island had grown less welcoming. Since the 2016 election, their conservative leanings have felt ever more out of step, they said, on an island whose political orientation is as blue as the sky above them. And they could sympathize with Mr. Dershowitz. After all, this island, which swells in the summer to more than 100,000 from the usual 15,500 year-round residents, picked Hillary Clinton with 71 percent of the vote.
“This is a very liberal island, this is like Vermont,” said the woman, an island resident with tight gray curls, who declined to give her name because she did not want to alienate her neighbors any more than she apparently already had. “It’s their way or the highway.”
The woman said she felt as if she had been ostracized from social events. “I remember one conversation and one of our friends who was a woman said, ‘only stupid people could vote for Trump, and they were the people in the middle of the country.’”
At the Chilmark General Store, where petunia baskets swing from a vast wooden front porch, families preparing for their Fourth of July barbecues emerged on Tuesday with pie boxes, baguettes and bags of locally grown greens.
“He’s a longtime Chilmarker — everyone knows him,” said Marianne Neill, a retired owner of a screen-printing business who said she leans liberal, of Mr. Dershowitz. “I know some people aren’t very happy with his defense of the president.”
But she said the area has a conservative streak, too, and his account of being ostracized does not square with the live-and-let-live town that she knows.