Specifically, trade war is causing Republicans considerable grief in farm country. Meanwhile, tariffs appear to be unpopular in industrial states, too. In fact, it’s hard to find any large group that likes Trump’s trade policy .

Why are Republican policy ideas falling so flat? At one level, the answer is obvious: G.O.P. policies are unpopular because they hurt far more Americans than they help. Why should anyone expect cutting taxes on the rich while taking health care away from the sick to be popular?

The question is why such policies were ever popular. The answer, I think, is that in the past, voters didn’t see the connections.

When Bush pushed through his tax cut, we had a budget surplus, so it wasn’t clear to voters that less revenue might mean cuts to programs they count on. When you push through big tax cuts in the face of a budget deficit — and when your own party has spent years warning about imminent fiscal doom and demanding spending cuts — the implications are more obvious.

In the case of health care, it was a lot easier to peddle scare stories about Obamacare before it went into effect, insuring tens of millions, than it is to defend taking away coverage people already have.

And Trump’s tariffs suffer politically because some Americans are already being hurt, while the supposed beneficiaries have good reason to doubt whether they will be helped. In fact, even as Trump boasts that his steel tariffs have revived the industry, two major steelworker unions have voted to go on strike — because while corporate profits have surged, workers’ wages haven’t.

In short, the American public seems to have wised up; voters seem to have recognized the G.O.P.’s reverse Robin Hood agenda of taking from ordinary families and giving to the rich for what it is.