Origin of “Smoking Gun”
The term originated from the idea that finding a gun that’s still smoldering on a murder suspect would almost certainly prove guilt beyond a reasonable doubt, being just one step away from catching the suspect doing the action itself.
The most famous example of a piece of “smoking gun” evidence in the history of politics is the Nixon “Smoking Gun” tape, which was a recording of Nixon speaking with Chief of Staff H.R. Halderman in the Oval Office on June 23, 1972.
The existence of this “smoking gun” recording directly led to the resignation of Nixon.
Nixon released the tape several weeks after it was recorded. On the tape you can hear three conversations Nixon had with Halderman soon after the infamous Watergate break-in. On the tape, Nixon admits to ordering a cover-up and encouraging the FBI to abandon its investigation.
The Nixon “smoking gun tape” had enormous consequences for the country and the presidency, as described in a Washington Post article commemorating the 40th anniversary of its release:
Yet the smoking-gun tape is still important because of what it tells us about the presidency in general. Because the bottom line of the White House order to ‘turn off’ the FBI’s investigation was that, for the most part, it didn’t work.
Since the Nixon tape and resignation, the term “smoking gun” has been used in the context of other political scandals.
Today, the term is used often to describe evidence in a scandal that could potentially provide irrefutable proof. The New Republic talks about why it is not always necessary:
That said, there may not turn out to be a “smoking gun”… If this or the next Congress follows precedent and reads history correctly, that won’t matter. In the case of Richard Nixon, the House Judiciary Committee had already voted to impeach him on three Articles of Impeachment before a recording emerged of Nixon telling an aide to order Pentagon officials to call the FBI to urge it to call off their investigation of Watergate.
During the investigation of Secretary of State Hillary Clinton’s emails and her server, Republicans searching for definitive proof of wrongdoing, or a “smoking gun,” either found it or didn’t find it, depending on what side of the aisle you were on.
More recently, during the impeachment of Donald Trump, many referred to the transcript of Trump’s call with the Ukrainian president as a “smoking gun,” as outlined in the fall of 2019 by publications like Mother Jones or in this Roll Call article: “We now have the smoking-gun summary, the most incriminating White House document since Watergate. Even with ellipses and maybe redactions for national security reasons, the reconstruction of Donald Trump’s July 25 conversation with newly elected Ukrainian President Volodymyr Zelenskiy is chilling in its specificity.”
Others would disagree, and of course in the case of Trump, the “smoking gun” outlined in the Roll Call article would not lead to his removal from office.
In 1997, a website called The Smoking Gun was launched to expose wrongdoing by officials and people in the public eye. They authenticate their reporting by “using material obtained from government and law enforcement sources, via Freedom of Information requests, and from court files nationwide.” One of the most famous cases of wrongdoing uncovered by The Smoking Gun was the fabrication of author James Frey’s memoir A Million Little Pieces.