In politics, a fishing expedition is a pejorative phrase to describe an investigation that lacks a clear scope and defined purpose. Fishing expeditions are usually carried out by members of one political party looking for damaging information about members of the opposing party.
On a literal level a fishing expedition involves casting out a line and then reeling in whatever you can; on a metaphorical level, a fishing expedition involves casting about for information that you may be able to use. Merriam Webster notes that the phrase was first used in 1874.
Nobody ever admits to being on a fishing expedition, of course; instead, the phrase gets flung around as an insult, usually by the person being investigated, or by their allies.
In March 2019, for example, House Democrats were investigating President Trump for alleged obstruction of justice and abuse of power. After the House requested documents from some of the president’s allies, President Trump tweeted that the investigation was:
The greatest overreach in the history of our Country. The Dems are obstructing justice and will not get anything done. A big, fat, fishing expedition desperately in search of a crime, when in fact the real crime is what the Dems are doing, and have done!
One year earlier, Trump advisor Kellyanne Conway promised that the White House would not carry out a “fishing expedition” against the then-nominee to the Supreme Court, Brett Kavanaugh. Conway told CNN that the White House was investigating allegations of sexual assault and misconduct which had been brought against Kavanaugh, but she pledged that the investigation “will be limited in scope, it’s meant to last one week, and … it’s not meant to be a fishing expedition.”
A few years earlier, Democrats were the ones railing against a “fishing expedition,” which is how many on the left referred to the investigation into Hillary Clinton’s handling of the 2012 Benghazi attack. “It is time, and it is time now, for Republicans to end this taxpayer-funded fishing expedition,” asserted Representative Elijah Cummings, during Clinton’s testimony to the Benghazi panel.
The “fishing expedition” hit an ironic peak in 2017, when Kenneth Starr told CNN that he was concerned that Special Counsel Robert Mueller might be overreaching in his investigation of alleged Russian interference in the 2016 US presidential election. Starr is best-known for his role as an independent investigator charged with looking into President Bill Clinton’s alleged crimes, from Whitewater to his relationship with Monica Lewinsky. At the time, Starr was widely accused of overreaching his own authority as an investigator.
Decades later, when CNN asked him for his reaction to the news that Mueller’s investigation had impaneled a grand jury, Starr said, “I do think it is a, certainly a serious matter when a special counsel is accused—and I was accused of that—of exceeding his or her authority. That’s a serious matter because we do not want investigators and prosecutors out on a fishing expedition.”