“It’s not that we simply shrug and move on in the face of a scandal. It’s that there’s immediately a new scandal to focus on,” she said. “One scandal is something you can sink your teeth into and focus on. Hundreds become white noise.”One person’s scandal is another’s moment of authenticity or admirable demonstration of political incorrectness or battle against the elitist “swamp” of Washington. The president’s base has remained remarkably constant over four years, hovering around 40 percent in most polls, largely unaffected by whatever outrages have consumed cable television on any given day — or energized by them in a way.For many of Mr. Trump’s admirers, it is the very fact that the establishment finds him so outrageous that binds them to him, a sign that he must be doing something right if the chattering class is so offended. Others see it as entertainment, never taking it too seriously, like his old reality television show. Or his supporters put aside any concerns because they appreciate his policies on taxes, trade, regulation, judicial appointments, military spending or overseas wars.“To an only modestly tuned-in public, the constant outrage, however justified, looks hysterical,” Ms. Longwell said. “There’s a lot of eye-rolling in the focus groups over the media constantly ‘freaking out’ about something Trump has done. They get worn out by ‘the negativity.’”The last week has been filled with freakout-inducing moments. After former Vice President Joseph R. Biden Jr. chose Ms. Harris as his Democratic running mate, Mr. Trump said he had heard “that she doesn’t meet the requirements” for the vice presidency because her parents were immigrants, even though she was born in California. Mr. Trump’s assertion has no basis in law but played to nativist sentiments and recalled his years of false suggestions that President Barack Obama was secretly born in Africa.Mr. Trump likewise resorted to some of his favorite terms for women he does not like, characterizing Ms. Harris as “nasty,” “angry” and a “mad woman.” Eric Trump, one of the president’s sons, “liked” a since-deleted tweet that referred to Ms. Harris as a “whorendous pick.”On the same day, the president played to old white fears by claiming on Twitter that “the ‘suburban housewife’ will be voting for me,” using a word more common in the 1970s than the 21st century, because if Mr. Biden wins he will force low-income housing into their communities “with Corey Booker in charge,” naming another Black senator (while misspelling his first name).