America is witnessing the “slow-motion crash” of Donald Trump’s presidency because the man at the top lacks discipline, Mayor Rahm Emanuel said Thursday.

“You have a President [who] just cannot function within order, within a system,” the mayor said, during an interview with his longtime friend David Axelrod for his “Axe Files” podcast.

“It’s hard to describe this as a modern White House. It may be a post-modern White House. But it’s not a White House.”

And how does it end?

“It’s gonna crash. You’re watching a slow-motion crash,” the mayor said.

“The biggest test of it will be on a core issue like taxes. …They’ve already jettisoned tax reform for tax cuts. If they cannot see their way to this, then you have the first true example that they cannot govern. … If you can’t get that and you’re Republican, it would be like us [Democrats] not being able to deliver some form of health care.”

The men served together in the White House; Emanuel was Barack Obama’s first chief-of-staff.

On Thursday, Emanuel sympathized with Gen. John Kelly, the man who holds that thankless job now and is trying desperately to stop the leaks and bring some semblance of order to the tumultuous Trump White House.

The mayor was responding to reports that Kelly was blindsided by Trump’s widely-condemned decision to twice blame “both sides” for the white nationalist rally-turned-deadly in Charlottesville, Va.

“I’m not worried about Kelly. … The biggest problem Kelly was gonna have is that the principal wasn’t gonna actually play by the Kelly rules,” the mayor said.

All week long, Emanuel has been harkening back to 1978, when he was a teenager who joined a Marquette Park protest to counter a city-sanctioned rally by a group of Nazis.

“I say this as Rahm Israel Emanuel, I want to know what the Jewish members of his administration think. At what point does your common decency and values get crossed?” the mayor said.

“I always said to everybody who worked with me in the White House, `There may be a point where a president makes a decision and you decided the job is not worth your values.'”

Emanuel’s reference to the Trump presidency as a “slow-motion crash” comes one day after yet another public broadside from U.S. Attorney General Jeff Sessions.

Speaking in Miami, Sessions tried again to link Chicago’s nagging homicide rate to illegal immigration and attacked the mayor for his pre-emptive lawsuit seeking to block Sessions from cutting off federal crime-fighting funds to sanctuary cities.

“If voters in Chicago are concerned about losing federal grant money, call your mayor,” he said.

On Thursday, Emanuel fired back at the attorney general with whom he still hopes to negotiate a memorandum of agreement on police reform.

“Immigrants, undocumenteds are not the driving force for gun violence. It’s access to guns. It’s repeat offenders back on the streets who need to be behind bars. And it’s also about economic opportunity and job creation,” the mayor said.

Referring to a private conversation he had with Sessions, Emanuel said, “I was willing to talk about after-school [programs and] summer jobs. He has no interest in that. And you can’t solve this problem if you’re not looking at all the aspects.”

Emanuel argued once again that Chicago’s status as a “welcoming city” helps fight crime because it encourages immigrants to work with police officers “rather than create a wall and a breakdown of community policing.”

Pressed on what he believes is behind Sessions’ attack, Emanuel said: “They’re playing politics with this. . . . And their data doesn’t hold up. It’s not factually true.”