And why ? Don’s $155M vote burn

President Trump is betting big on the primaries.

With no serious challengers for the Republican Party nomination and high GOP approval numbers, Trump could have cruised through the spring campaign season like most incumbent presidents do.

Instead, he traveled to 18 states for campaign rallies and spent more than $155 million to rack up high primary-vote totals for a nomination he had virtually no chance of losing.

“I don’t remember any uncontested primary campaign for a sitting president like this,” Stony Brook University political-science 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 Barack 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 primaryvote totals also beat President George W. Bush’s totals in 2004.

The high Trump turnout showed up in reliably Republican states like Montana and Arkansas and in deep-blue strongholds and purple states that Joe Biden hopes to flip come November.

In Michigan’s March primary, Trump’s 639,144 votes dwarfed the 174,054 that Obama notched in 2012.

A few weeks later, Trump scored 713,546 votes in Ohio, more than twice Obama’s 2012 total of 285,990.

The campaign has made a heavy get-out-the-vote effort in each primary state as a dry run for its general-election turnout operation. And it’s using Trump’s rallies to vacuum up supporters’ data and register new voters, fueling its November plans.

The primary push has a sound psychological basis, said Norpoth, an expert in voter behavior.

“If you can get people to come out for a primary that isn’t even a contest, you have them hooked.”