“I don’t remember any uncontested primary campaign for a sitting president like this,” Stony Brook University professor Helmut Norpoth told The Post. “People don’t normally turn out in large numbers for a race without a challenger.”

But in 23 of the 27 states that held primaries both this year and in 2012, when President Obama ran for re-election, Trump has racked up higher raw vote totals than Obama did — often doubling or tripling his predecessor’s numbers. His primary vote totals also beat President George W. Bush’s in 2004.

The high Trump turnout showed up not only in reliably Republican states like Montana and Arkansas, but even in deep-blue strongholds and in purple states that Joe Biden hopes to flip come November.