DANIEL HENNINGER: The Incompetence Party. “The Democrats’ biggest problem isn’t Bernie Sanders. It’s that many voters doubt the party’s ability to govern anymore.”

The Iowa caucus debacle came on top of the Trump impeachment, another low-turnout event with the public. People began telling reporters that the three-year death struggle between Democrats and President Trump wasn’t their idea of Washington’s purpose.

So what, other than hunting Donald Trump, does the Democratic Party stand for?

A recurring argument of this column is that in the U.S. and Europe, the presumed efficiency of governments has been worn down by the programs and responsibilities they’ve created for themselves, some with good intentions. By now, it’s just too much.

During the Depression, Franklin Roosevelt struck a defining bargain with the public: Cede to the government expanded powers over the details of American life, and government will administer it efficiently. For the public, giving government the power to regulate and rule was supposed to be a net plus.

The bargain behind Bernie Sanders’s Medicare for All, funded by new taxes on the middle class, is that it too will be a net plus. Come Election Day in November, will 50% of the electorate actually believe Democrats today could competently administer a national health-care system in the U.S.?

Mr. Sanders, who filed as a Democrat for this election, isn’t that much of an outlier. All his rivals, including the “moderates,” are proposing more additions to the already massive government labyrinth they’ve built for decades.

But in those places where the modern Democratic Party is in charge, they often govern badly or incompetently on a grand scale.

Detroit, from coast to coast.