Now Obama is accusing Donald Trump of being “unfit” to be president. Of being “woefully unprepared” and lacking “basic knowledge.”

Fill in your own schoolyard cliche. “I know you are but what am I?” People in glass houses shouldn’t throw stones — Obama once said that he read that in the Bible.

And he puts the blast on someone else for lacking “basic knowledge.”

Brave talk from a guy who thinks there are 57 states, that they speak Austrian in Austria, that they speak Arabic in Afghanistan, who pronounced the state he lived in for three years as “Mass-a-tu-setts,” who pronounced corpsman as “corpseman.” Who thinks the Transcontinental Railroad was “intercontinental.”

He described Eric Holder’s wife, a physician, as a “nationally renowned ohbee-gynee.” He misspelled “Syracus” on his NCAA brackets sheet. He is utterly tongue-tied without a teleprompter. He makes “recess” appointments when the Senate is not in recess.

If he had a son, he would look like Trayvon Martin. His grandmother was a typical white person. The Cambridge Police Department acted stupidly.

It never ends with this buffoon. Yesterday, in Singapore, he mangled the name of the country’s founding father. He can’t be bothered acting like an adult. He chews gum in public. Remember how he took selfies of himself with the Danish hottie at Nelson Mandela’s funeral?

The media were all over Trump like white on rice yesterday because he was goofing around with a baby at a rally. But Obama gets a base on balls on absolutely everything. If his middle name weren’t “Hussein,” it would be “Entitlement.”

“If you like your doctor you can keep your doctor. … If you like your health care plan you can keep your health care plan. … You’ll save $2,500 on your premiums.”

The Red Line in Syria. Shovel-ready jobs that he later had to admit (while chuckling) weren’t really shovel-ready. Making jokes about the Special Olympics. Dismissing ISIS as “the JV team.”

For a guy who is always prattling about “teachable moments,” he doesn’t seem to have learned much in all his foolish years, as Sinatra would say. (I can hear Obama asking now, “Who?”)

But he says Trump is the one who “doesn’t appear to have basic knowledge.”

He traded five Gitmo terrorists to get back a deserter (Bowe Bergdahl). Fast and Furious. Brooming the New Black Panther voter-intimidation cases in Philadelphia. Referring to the Constitution as “that paper.” Dismissing the Muslim terror murder of 13 U.S. servicemen at Fort Hood as “workplace violence.” Lois Lerner of the IRS.

Unfit to be president?

“Trump gets grief for eating KFC on his 757 with a knife and a fork. But Obama admits eating dogs, and no one mentions it, although that may be because he copped to it in one of his narcissistic unread “books” that everybody bought and then left on their coffee tables, unread, to assuage their white guilt.

Unfit? Woefully unprepared? Lacking basic knowledge?

Hey Obama, it takes one to know one.

Listen to Howie 3-7 p.m. on WRKO AM 680.