So much grist poured out of the president’s relentless and reckless rant in Phoenix …

Let’s take a nibble at this tidbit: Donald John Trump Sr. says he’s willing to shut down the federal government if Congress doesn’t approve money to pay for the wall to be built along our nation’s border with Mexico.

Yep, the guy who said this past summer that “I, alone” can solve the nation’s problems now is blackmailing congressional Democrats to provide money to build the wall. If they don’t, he said, the government shutdown is on their hands.

But wait!

Trump has vowed that Mexico is going to pay for the wall. Mexico’s President Enrique Pena Nieto says “no … we won’t!” Trump reportedly has zero relationship with the Senate’s top Republican, Mitch McConnell, who has declared there is “zero chance” the government is going to shut down; “We are not going to default,” said McConnell.

The president is insulting congressional Republicans as frequently as he insults Democrats. He is destroying — one insult at a time — any chance of getting anything done once Congress returns from its summer recess.

So now the guy who wants to “unify” the country, who declares it is time to “heal our divisions” is now threatening to shut down the federal government if Congress doesn’t do something he has promised never would happen.

I believe former Director of National Intelligence James Clapper — a serious and sober man — has it right. Donald Trump is unfit for the job to which he was elected.