Prof. Alan Dershowitz (Getty Images/Lior Mizrahi)

“Nancy Pelosi doesn’t understand what impeachment is,” renowned Harvard Law Professor Alan Dershowitz said Tuesday, debunking House Speaker Nancy Pelosi’s (D-Calif.) proclamation that, even if acquitted, President Donald Trump will be “impeached forever.”

An “impeachment” is simply a grand jury presentation and – just as being found innocent by a jury removes an indictment – a Senate acquittal makes an impeachment "disappear," Dershowitz explained in a Fox News Channel interview with host Sean Hannity:

"Nancy Pelosi doesn't understand what impeachment is. “What she has said is, even if the president is acquitted, the impeachment stands - No." "That's like saying that, if a person is indicted and the jury acquits 12-0 in five minutes, he’s still indicted." "No - the impeachment disappears. The impeachment is only a grand jury presentment."

Some Democrats even wanted to impeach President Ronald Reagan for “abuse of power,” Dershowitz recalled. If Reagan could be impeached for that, so could every U.S. president in history, he concluded.