It remains something of a mystery why there is so little apprehension among liberal pundits and leading Democrats about the similarities between battleground-state polling for the 2020 presidential election and the 2016 contest pitting President Trump against Hillary Clinton — which as you might recall did not turn out as expected.

Consider the case of Wisconsin.

The RealClearPolitics average had Clinton up 6.5 points in Wisconsin on Election Day in 2016. In August of that year, she had been hovering at an 11.5-point advantage. Not a single poll featured on RCP during the entire campaign showed then-candidate Donald Trump winning the state. Yet when the chips were down in November, Trump had won the Badger State by fewer than 20,000 votes, edging out Clinton with a 0.7 percentage-point average.

Now turn to 2020. As I write, Democratic Party nominee Joe Biden is up by 3.5 points in the RealClearPolitics average — which is to say, the ex-veep is underperforming Clinton in the middle of a pandemic and the economic collapse caused by the lockdowns.