Former President Barack Obama took some subtle shots at President Donald Trump and named the one thing he believes American democracy cannot survive during a Tuesday night interview with “Late Show” host Stephen Colbert.

Obama didn’t name Trump directly, but he did suggest that the current president has completely upended the unwritten rules of the office.

“We’re going to have to do some work to return to this basic norm, and we probably now have to codify it,” Obama said. “The White House shouldn’t be able to direct the attorney general to go around prosecuting whoever the president wants prosecuted.”

The former president was likely referring to attempts made by Trump’s Justice Department to prosecute his perceived political enemies, such as former FBI Director James Comey and New York Attorney General Letitia James.

“There’s a bunch of stuff that we can overcome,” he said, naming bad policy and “funky” elections as examples.

But he warned that the nation can’t overcome the politicization of the criminal justice system.

“You can’t have a situation where whoever is in charge starts using that to go after their political enemies. Or reward their friends,” he said.

Obama also had some suggestions, again with a specific ― but unnamed ― person in mind:

While Obama didn’t use Trump’s name even once during the lengthy interview, a number of things he mentioned as abuses of power line up with many things Trump has done during his second term in office — including the politicization of the military and using the presidency for personal financial gain.