Their complaints, in some cases, have some validity, but not always and not a lot. Economist Gordon Hanson writes that without the ability to move lower-wage jobs to Mexico after NAFTA was ratified in 1993, "there might not be much left of Detroit at all." Which is to say, the U.S. wouldn't have the 800,000 relatively high-wage auto-sector jobs it has today.
As for the reviled Republican congressional leaders, anyone familiar with the Constitution should know that the president has the power -- and in this case the inclination -- to veto any conservative legislation Congress passes.
Demographic analysis shows that Trump is getting disproportionate support in primaries from white male non-college graduates with modest incomes -- a group that, as The New York Times' Thomas Edsall notes, has been giving Republicans large margins in general elections.
And Trump's appeal amounts for some quantum -- no one can be sure exactly how much -- of the increased Republican turnout this year. So far 21 million Americans have voted in Republican primaries and caucuses, as many as in the whole 2008 cycle and nearly 2 million more than in 2012.
But Trump supporters also seem to have something else in common, as I argued in a recent column -- a lack of social connectedness. They are less likely than average to be active in voluntary associations and in churches, in community activities and in extended families.
They seem to see Trump, a familiar figure from his reality TV show, as a single figure who can, without institutional support or coherent philosophy, right the wrongs they complain of.
When you look at a map of the counties Trump has carried in primaries, prominent among them are places with slumped industrial economies and closed factories, such as Youngstown and the Ohio counties along the Ohio River. They are places where family structures are crumbling, male life expectancy is declining, opioid addiction is common and up to one-fifth of adults receive disability insurance payments.
In writing of such places National Review's Kevin Williamson describes "the welfare dependency, the drug and alcohol addiction, the family anarchy -- which is to say, the whelping of human children with all the respect and wisdom of a stray dog."
I wouldn't be so harsh. But the fact is that Disability Insurance rolls have more than doubled in the last two decades, and about half the applicants claim ailments -- back pain, depression -- that are unverifiable.
DI recipients can live in such places on $13,000 annual benefits. But it's hard for them to gain the satisfaction that comes from earning success at work, raising your family and serving your community.
What such people need, Williamson says, is not OxyContin but U-Hauls. But mobility -- moving from one place to another -- in America has been declining for a generation. There is little out-migration from the Ohio River counties, much less than there was from Youngstown when steel factories closed 35 years ago.
Then there was moaning about the fate of people uprooted from their lifelong communities to move to fast-growing places like Texas. Moving is a pain, but it struck me that people leaving Youngstown were less painfully uprooted than their grandparents were when they moved there from rural Poland.
Earlier generations of Americans, after being moved around the country and the world in World War II, moved readily to seek better lives. Several million Midwesterners moved to California. One-third of American blacks moved from the segregated South to what seemed the promised land of the North.
Inadvertently perhaps, we have made it easier to stay put, through disability insurance, through low-priced goods at Wal-Mart and its competitors, through opioid prescriptions written by dollar-hungry doctors -- even as family and community ties grow frayed.
People in such situations evidently see themselves as victims and Donald Trump as someone who will make them winners again. Their sense of victimhood resembles that of the Emory University students who couldn't bear seeing "Trump 2016" chalked on the sidewalk.
Those victims could easily have solved their problem themselves. Maybe protesting Trump voters can, too.