On Monday, Sen. Mike Lee (R-UT) laid out a detailed plan to bring back the old tactic of privateering, in which the government would give private actors its blessing to raid enemy ships, taking part of the loot as payment. Though the practice was largely ended by the 1856 Paris Declaration Respecting Maritime Law after the Crimean War, Lee suggested reviving and modernizing it.

“Congress could issue letters of marque and reprisal authorizing private security firms or specially trained civilians to intercept cartel operations, particularly those involving drug shipments or human trafficking across borders,” Lee suggested after pointing out that the Constitution still gives it authority to issue the letters.

The privateers would “focus on disrupting supply lines, capturing high-value targets, or seizing assets like boats, vehicles, cash, gold, or equipment used in criminal activities.”

Lee argued that the move would allow more flexibility in combating threats from drug cartels and save taxpayer money. His proposal drew support from several of those close to President Donald Trump.

“If you’re looking for an effective, efficient, @DOGE-compliant way to combat Mexican drug cartels — especially those now threatening to target U.S. planes deporting illegal aliens — you will really like this thread proposing letters of marque and reprisal as a possible solution!” Trump Jr. said in a post on X, quoting Lee’s proposal.

“This would work very fast,” Musk said in an X post quoting the proposal.

Lee’s proposal largely drew praise and memes on social media, with many Trump supporters voicing their approval. Other critics were more skeptical, with some pointing out logistical problems with the plan.

“Letters of Marque and Reprisal were effective in the past because privateers could legally sell the ships and cargo they captured. The most valuable property that drug dealers own is drugs. Would the government let the privateers sell the drugs they capture?” the Cato Institute’s Alex Nowrasteh said.

The Daily Beast’s Janna Brancolini called the proposal “crazy.” She said the primary reason for letters of marque in the United States’s case was to compensate for the lack of a sizeable navy — in stark contrast to the military power the U.S. is today.

Monday wasn’t the first time Lee floated the idea — he first mentioned the power in a 2011 Conservative Political Action Conference speech. However, the speech was less a proposal than a history lesson.

He explained that letters of marque are “essentially a hall pass issued by Congress that entitles the bearer to act in the United States’s name and engage in state-sponsored acts of piracy on the high seas.”

“And so, help me, if it’s the last thing I do … I’m going to get a letter of marque of reprisal,” he said, drawing laughter. “I’m going to get a ship and an eyepatch, and I’m going to be a pirate, and you’re all invited to join me!”

Lee’s Monday proposal also resembles the more modern filibustering, in which people would gather private armies to invade Latin American countries with the intention of setting up their own governments, sometimes with the tacit blessing of the U.S. government.

The most successful, William Walker, conquered Nicaragua in 1856.