Alan Dershowitz made waves in the political universe Wednesday by offering a sweeping view of presidential power in his argument before the U.S. Senate during President Donald Trump's impeachment trial.

"Every public official that I know believes that his election is in the public interest," Dershowitz said Wednesday. "And if a president does something which he believes will help him get elected in the public interest, that cannot be the kind of quid pro quo that results in impeachment."

See all of our impeachment coverage here.

But five decades ago, Dershowitz advocated a much more limited view of executive privilege and even said the House should demand then-President Richard Nixon testify under oath.

In the early 1970s, as the House was considering impeachment proceedings against Nixon, Dershowitz presented a different argument while appearing on a special episode of "The Reporters," a WGBH News program. In the one-hour episode, which aired on Nov. 1, 1973, Dershowitz appeared with several other legal scholars to debate the theme "Treason, Bribery Or Other High Crimes and Misdemeanors."

"When you smell smoke as a prosecutor, when you think something is awry," Dershowitz said, about 29 minutes into the video above, "you call the man in front of a grand jury and you call the man in front of the grand jury under oath. The president of the United States has never appeared under oath."

He went on to argue that impeachment proceedings were created to ensure that any president would have a proper check on their power.

"Executive privilege, if it applies at all, the impeachment process — viewed as a very broad process ... was certainly designed as a way of overcoming the invocation of executive power," he said. "I would like to see the president of the United States invoke executive authority when called before the House Judiciary Committee and asked to answer under oath, to repeat under oath, the statements he said on television."

The comments were part of a broad discussion about whether the U.S. had enough information to impeach Nixon based on the president's actions and public statements, or whether — as Dershowitz argued — the House needed to convene a more formal investigation equivalent to a grand jury.

Another panelist scoffed at Dershowitz' notion of ordering the president to testify.

"What are you going to find out from the president?" asked Boston University law professor Henry Monaghan. "What are you going to find out by asking him questions?"

"Perjury is a mighty weapon," Deshowitz responded.

He said that the president's refusal to appear before the House would not in itself be a "high crime and misdemeanor." But it would allow the House to make inferences about his guilt because "you are allowed to accept inferences when a witness who was available and could appear does not appear and deny."