Lead House impeachment manager Rep. Adam Schiff (D-CA) argued less than a year ago in the Washington Post that a president had a duty to investigate a candidate from the rival party if he was suspected of foreign corruption.

Schiff, reacting to Special Counsel Robert Mueller’s report on “Russia collusion,” justified the Barack Obama administration’s counterintelligence investigation of the Trump campaign, and said Mueller should have included it.

Schiff wrote that investigating a potential president — even from the opposition — was an urgent matter of national security if there were reason to believe that candidate were working for, or beholden to, a foreign country.

He wrote (emphasis added):

Counterintelligence investigations differ from criminal investigations in their means, scope and ultimate disposition. Their goal is not successful prosecutions, but to identify and mitigate threats to national security. If a foreign power possessed compromising information on a U.S. government official in a position of influence, that is a counterintelligence risk. If a foreign power possessed leverage, or the perception of it, over the president, that is a counterintelligence nightmare.

Schiff added that the public deserved to see the material that the FBI found on the Trump campaign. (We know today that the FBI lied to the FISA court to obtain surveillance warrants on a Trump aide.)

Today, Schiff and the Democrats are arguing that it is an impeachable offense for a president to investigate foreign corruption by a potential president from the opposition — even when, as in the Bidens’ case, former Vice President Joe Biden had a clear conflict of interest while his son, Hunter, was on the board of Ukrainian company Burisma.

According to Schiff just last April, it is not an impeachable offense, but an urgent matter of national security for a president to investigate his potential successor.

It is the president’s duty. That is, unless the president is Donald J. Trump.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.