Former President Barack Obama made some pointed remarks about the state of American governance under President Trump in an interview with Stephen Colbert that aired Tuesday night. Obama raised concerns about the expansion of executive branch powers and the use of the Justice Department for political ends, though he didn't mention Mr. Trump by name.

"We can survive a lot — bad policy, funky elections, there's a bunch of stuff that, you know, we can overcome," Obama said on "The Late Show with Stephen Colbert." "We can't overcome the politicization of our justice system, the awesome power of the state. You can't have a situation in which whoever is in charge of the government starts using that to go after their political enemies or reward their friends."

When Colbert asked about the "need to restrict executive powers" and "what powers do you believe the president should not have," Obama said "there are a couple that I followed even though they weren't law. I want us — we're going to have to do some basic work to return to this basic norm, and now we probably have to codify it." 

"The White House shouldn't be able to direct the attorney general to go around prosecuting whoever the president wants to prosecute," Obama said. "The norm is — the idea is that the attorney general is the people's lawyer. It's not the president's consiglieri." 

Obama said the Justice Department needs to be "independent in making judgments about specific cases and prosecutions."  Under the current administration, the Justice Department has attempted to prosecute a number of Mr. Trump's adversaries, including former FBI Director James Comey and New York Attorney General Letitia James. 

During the nearly 25-minute interview, Obama also discussed presidential pardons. He noted that pardon power is in the Constitution, but said, "maybe don't pardon people who've given you a bunch of campaign contributions."

Another area where he expressed concern is politicization of the military.

"There had been a whole series of norms that were in place to ensure that you weren't trying to make the military loyal to you, as opposed to the Constitution, and the people of the United States," Obama said. "We're going to have to find mechanisms to restore that." 

Obama said a "pretty obvious principle" that he would like to see is that the president "should have a bunch of side hustles that companies, foreign entities, can invest in." 

Obama spoke with Colbert ahead of the opening of the Obama Presidential Center in Chicago, which is set to open to the public on Juneteenth. Obama said he hopes it will help people to think about "this extraordinary journey this country took to get to" his presidency. 

"It's this struggle between the idea that 'we the people' includes everybody — that's it's just some, it's not just some select few," Obama said. 

Historically, former presidents have mostly avoided public criticism of their successors, but Mr. Trump has frequently criticized Obama and his policies as well as the Biden presidency. 

Obama has also spoken out about Mr. Trump on the campaign trail. He told The New Yorker in an interview released earlier this week that Mr. Trump's actions have prompted him to be involved "more than I would have preferred," but he said he felt that if he criticized everything it would diminish the impact.

Colbert is doing a farewell tour ahead of his final "Late Show" episode, which is set to air on May 21. When Colbert asked if he should run for president next, Obama joked "I think it's a stupid idea" but then added "the bar has changed." 

"I put it this way: I think that you could perform significantly better than some folks that we've seen," Obama said.