Joe Biden says that he believes prosecuting a former president would be a "very unusual thing and probably not very ... good for democracy," but he would not stand in the way of a future Justice Department pursuing criminal charges against President Trump after he leaves office.

The comments from the presumptive Democratic presidential nominee came during a virtual interview Tuesday with members from the National Association of Black Journalists and National Association of Hispanic Journalists.

"Look, the Justice Department is not the president's private law firm. The attorney general is not the president's private lawyer. I will not interfere with the Justice Department's judgment of whether or not they think they should pursue the prosecution of anyone that they think has violated the law," Biden told NPR's Lulu Garcia-Navarro.

Trump has been connected with alleged illegal activity by his former lawyer and fixer Michael Cohen and investigators working for former special counsel Robert Mueller. What isn't clear is whether federal authorities are investigating the president or whether prosecutors might take action against Trump if he no longer enjoyed the privileges that protect him from being indicted as a sitting president.

Biden made clear that any future prosecution against Trump would not be directed by him if he's elected president.

"In terms of saying, 'I think the president violated the law. I think the president did this, therefore, go on and prosecute him' — I will not do that," he said.

"If [a case] prove[s] to be a criminal offense, then in fact, that would be up to the attorney general to decide whether he or she wanted to proceed with it. I am not going to make that individual judgment," Biden added.

Sen. Kamala Harris of California told The NPR Politics Podcast last year that if elected president, her administration's Department of Justice would bring criminal charges against Trump after his presidency, saying, "I believe that they would have no choice." Harris is a top contender on Biden's shortlist for vice president.

Immigration

Biden also told Garcia-Navarro that he would not tear down parts of the wall along the U.S. southern border built during the Trump administration, but he vowed to end its construction.

When asked about asylum-seekers waiting in camps in Mexico due to the Trump administration's policy known as "Remain in Mexico," Biden said reversing Trump's policies will have to be done with care.

"Because if we just say, 'OK, all done. I've withdrawn the order,' you're going to have a crisis on the other side of the border as well," Biden said. "And we shouldn't be putting these people when they come across the border in jail; we should be monitoring them."

Watch Biden's response on rolling back Trump immigration policy:

The controversial "Remain in Mexico" policy, officially named the Migrant Protection Protocols, was first implemented in January 2019 and mandates that asylum-seekers coming through Mexico wait outside the U.S. while their immigration proceedings take place. As NPR's Vanessa Romo reported, the policy has led to 60,000 migrants getting sent back across the border, with tens of thousands still there.

The U.S. Supreme Court decided in March to allow the program to continue.

Biden added that a push for more humanitarian resources is needed and said that Immigration and Customs Enforcement "is going to go back to school."

"The idea that ICE is sitting outside of a Mass on Sunday to arrest a parent coming out as undocumented, the idea that they're going to schools, the idea they're going to doctors' appointments is wrong," Biden said. "You have so many young children, so many young children under enormous ... psychological pressure wondering whether or not they're going to come home and there's going to be no one there."

Choosing a running mate

Biden declined to offer new insight into his thinking for a vice presidential pick, telling the journalists, "You'll find out shortly."

CBS' Errol Barnett pointed to reports that former Sen. Chris Dodd, who's on Biden's vice presidential search committee, has been critical of Harris for not having a more conciliatory tone toward Biden in the early primary debates.

"Well, [Dodd] didn't say that to the press. He was talking to somebody offline, and it was repeated," Biden said. "Now, I don't hold grudges, and I've made it really clear that I don't hold grudges. I think it was a debate. It's as simple as that. And she's very much in contention."

Watch Biden's response on VP speculation:

Reopening schools and businesses

Biden said it's challenging to foresee what the country would look like in January if he were entering office then, but he said he would scale back reopenings in places seeing spikes of the coronavirus if he were president today.

"Everyone, wherever there is a significant percentage of people with COVID, should be required to keep social distancing and masks," Biden said. "Bars should not be open. There should not be congregations of more than 10 people."

As for the Trump administration's desire to reopen schools this fall, Biden said it only works if it's done safely.

"Look, I want our schools to open. The question is, will the president do the work he needs to make them safe? Just ordering your schools to open, like Trump has done, isn't going to be good enough," he said.

Biden's plan includes giving school districts "uniform guidance without political interference" on safety protocols for schools that are able to reopen, directing resources to districts to implement guidance and bolstering virtual learning for districts that can't reopen safely.

"Start working now to close the learning gap in terms of distance learning because of COVID. President Trump should stop tweeting and start doing his work," he said.

Election security

"Frankly, this is the thing that keeps me up most nights," Biden said in response to a question from The Atlanta Journal-Constitution's Tia Mitchell about voter confidence in a secure election. "Making sure everyone who wants to vote gets to vote, making sure that everyone's vote is counted. And we're going to undertake a historic effort in terms of resources, commitment to beat back every voter suppression effort."

"No campaign has ever built anything to the scale that we've built to make sure we can get out the vote. We have a major, major dedicated operation in states to address the head-on voter suppression in any form that it's going to take, and steps we can take to go to court as well," he said.

The pandemic has caused election experts to worry about a shortage of poll workers for the general election, and states are preparing for an increase in mail-in voting this fall.

The White House has repeatedly advanced conspiracy theories surrounding the integrity of mail-in voting, and Trump went so far as to suggest delaying the November election based off the false claim that mail-in voting can be "rigged."

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