What is presidential immunity? Supreme Court ruling broadens definition in Trump v. United States ruling

On Monday, the Supreme Court ruled that former President Donald Trump is immune from prosecution for his “official acts” in office. Well, at least for some of them. Just what does that mean?

Trump v. United States was brought before the court to determine if prosecutors could seek charges against Trump for trying to overturn the 2020 election or if he would be immune from prosecution because he was the sitting president at the time. The court ruled, in a 6-3 vote, that presidents are in fact shielded from prosecution for official acts, but they weren't as clear on questions raised about Trump's role in reported election interference and the Jan. 6 Capitol riot.

That decision they saved for the judge in the federal case to rule on, with Chief Justice John Roberts writing, "That analysis ultimately is best left to the lower courts to perform in the first instance."

Many of us know that presidents have some form of immunity while they are president, but here's what it entails and what the Supreme Court's decision means in the ongoing Trump prosecution and trials.

What is presidential immunity?

There is nothing in the Constitution that gives presidents immunity in civil or criminal legal proceedings, but there have been other Supreme Court decisions that have set the precedent of what we think of as presidential immunity.

Presidential immunity is when a sitting president has both civil and criminal immunity for actions relating to the official duties of the president, including those in the "outer perimeter" of those duties. This immunity does not extend to unofficial conduct, criminal conduct and conduct occurring before becoming president.

According to Congress.gov, a 1867 Supreme Court decision in Mississippi v. Johnson, established that the president is largely beyond the judiciary's reach by, "holding that it could not direct President Andrew Johnson in how he exercised his 'purely executive and political powers.' The Court stated, it had 'no jurisdiction . . . to enjoin the President in the performance of his official duties.'"

But that decision didn't mean a president was immune to all judicial processes.

When it comes to lawsuits, sitting presidents are immune from being part of them, but in cases ― like in former President Richard Nixon's Watergate scandal― the Supreme Court has ruled that presidents have to provide documents and may have to appear in court during the legal proceedings.

What does the Supreme Court's case mean for Trump's presidential immunity claim?

The ruling in Trump v. United States states that Trump is entitled to immunity from criminal prosecution for conduct that is part of "official” acts as president but not "unofficial" acts he took as a candidate.

USA Today contributed to this story.