Sanders and his supporters boast of polls showing him, on average, matching up slightly better against Trump than Clinton does. But those matchups are misleading: Opponents have been attacking and defining Clinton for a quarter- century, but nobody has really gone to work yet on demonizing Sanders.

Watching Sanders at Monday night’s Democratic presidential forum in Des Moines, I imagined how Trump — or another Republican nominee — would disembowel the relatively unknown Vermonter.

The first questioner from the audience asked Sanders to explain why he embraces the “socialist” label and requested that Sanders define it “so that it doesn’t concern the rest of us citizens.”

Sanders, explaining that much of what he proposes is happening in Scandinavia and Germany (a concept that itself alarms Americans who don’t want to be like socialized Europe), answered vaguely: “Creating a government that works for all of us, not just a handful of people on the top — that’s my definition of democratic socialism.”

But that’s not how Republicans will define socialism — and they’ll have the dictionary on their side. They’ll portray Sanders as one who wants the government to own and control major industries and the means of production and distribution of goods. They’ll say he wants to take away private property. That wouldn’t be fair, but it would be easy. Socialists don’t win national elections in the United States .

Sanders on Monday night also admitted he would seek massive tax increases — “one of the biggest tax hikes in history,” as moderator Chris Cuomo put it — to expand Medicare to all. Sanders, this time making a comparison with Britain and France, allowed that “hypothetically, you’re going to pay $5,000 more in taxes,” and declared, “W e will raise taxes, yes we will.” He said this would be offset by lower health-insurance premiums and protested that “it’s demagogic to say, oh, you’re paying more in taxes.”

Well, yes — and Trump is a demagogue.

Sanders also made clear he would be happy to identify Democrats as the party of big government and of wealth redistribution. When Cuomo said Sanders seemed to be saying he would grow government “bigger than ever,” Sanders didn’t quarrel, saying, “P eople want to criticize me, okay,” and “F ine, if that’s the criticism, I accept it.”

Sanders accepts it, but are Democrats ready to accept ownership of socialism, massive tax increases and a dramatic expansion of government? If so, they will lose.