NICK KRISTOF: I worry about Sanders, and his coattails.

There is one kind of candidate that Americans remain hostile to. Only 45% say that they would be willing to vote for a socialist. And Sanders faces another hurdle: Only 69% say they would consider a candidate over 70.

These are generic questions, and it’s possible that voters would warm to a particular septuagenarian socialist, especially when the alternative is a certain septuagenarian Republican. In head-to-head polls against Trump, Sanders does well; all Democrats do similarly. Yet I keep thinking of how British voters recently overwhelmingly reelected a deeply flawed conservative leader over a socialist challenger.

Supporters of Sanders believe that he would greatly increase turnout, but there was no sign of that in Iowa or New Hampshire. Sanders won in New Hampshire only because the liberal wing of the party is uniting around him, while the moderate wing is deeply divided.

I’m not getting cocky, but I am feeling unusually happy.