SCHRODINGER’S CANDIDATE: The Strangest Campaign in History? Joe Biden may be running for president — and then again, maybe he’s not.

And yet if Biden were to explicitly and publicly advocate the Sanders, AOC, or Warren neo-socialist agenda, he would also lose, turning off his supposed swing-voter and independent suburban constituents.

So Biden in the vortex stays nearly mute — a quietude certainly well suited to his age, the prior news cycles of 2020, his cognitive limitations, and his hope that he can win with a rope-a-dope, run-out-the-clock strategy.

And now? The polls tighten. This strange year is gradually normalizing. Biden should be rested, after his months-long hiatus. And so will he in the eleventh hour actually conduct a campaign? Yes and no.

His strategists still seem to suffer from the Hillary disease. As in 2016, Trump is frenetic in the swing states, the Democratic candidate is virtually nonexistent.

As in 2016, Biden and the Democrats talk of a 70 to 90 percent likelihood of victory and an Electoral College blowout. They speculate about who will be the nation’s next cabinet officers, oblivious that such arrogance only feeds their blindness.

As in 2016, a few polls — Rasmussen, Trafalgar, Emerson, Zogby — show Trump nearly even or ahead in some states and are thus dismissed. Mainstream polls, as in 2016, likely “prove” their absence of bias by under-sampling working-class Democratic constituencies and over-sampling suburbanites, many of them Republicans — as if they cannot be accused of party asymmetries even as they do not reflect accurate ideological affinities.

And the polling outfits that in 2016 assured a Clinton victory are now once against cited for their reassurance that the Democrat remains clearly ahead.

Don’t get cocky.