Billionaire Elon Musk escalated his attacks against White House trade adviser Peter Navarro on Tuesday, calling him a “moron” who’s “dumber than a sack of bricks.”

Musk, 53, responded Tuesday to the trade adviser’s suggestion on CNBC’s “Squawk Box” Monday that the Tesla boss was “not a car manufacturer” but “a car assembler,” pointing to the electric vehicle company’s importing of batteries and other key components to manufacture its cars. 

“Navarro is truly a moron. What he says here is demonstrably false,” Musk wrote on X, adding in a subsequent post in which he tagged the “Re—d Finder”: “Tesla has the most American-made cars. Navarro is dumber than a sack of bricks.”

“By any definition whatsoever, Tesla is the most vertically integrated auto manufacturer in America with the highest percentage of US content.” Musk continued. “Navarro should ask the fake expert he invented, Ron Vara.”

In his screed against Navarro, Musk cited a Cars.com study of 338 cars in 2023 that concluded Tesla had four of the top five American-made cars. However, that study counted Canada as part of the US.

Musk also later bashed Navarro as “Peter Re—d-o.”

White House press secretary Karoline Leavitt downplayed Musk and Navarro’s feud Tuesday afternoon and praised Trump for his “willingness to hear from all sides.”

“These are obviously two individuals who have very different views on trade and on tariffs,” Leavitt told reporters during her regular press briefing. “Boys will be boys and we will let their public sparing continue. You guys should all be very grateful that we have the most transparent administration in history.”

Over the weekend, Musk had first taken swipes against Navarro, 75, seemingly irked by President Trump’s onslaught of tariffs last week that Navarro played a pivotal role in crafting.

Musk had chided Saturday that Navarro’s Harvard education — he holds a master’s and Ph.D. from the Ivy League university — “is a bad thing, not a good thing,” prompting the trade adviser to accuse the world’s richest man of trying to protect his own interest.

“Elon, when he’s in his DOGE lane, is great, but we understand what’s going on here. Elon sells cars. He’s simply protecting his own interests,” Navarro told Fox News Channel’s “Sunday Morning Futures.”

US stocks jump as trading partners rush to negotiate with Trump on tariffs

“There’s no rift here. Look, Elon, he’s got X, he’s got a big microphone. We don’t mind him saying whatever he wants. But, just, the American people need to understand that we understand what that’s all about, and it’s fine,” Navarro added.

Last week, Trump, 78, announced the highest rate of tariffs on foreign countries in nearly a century, including a 10% baseline rate on virtually every country that took effect at 12:01 a.m. Saturday and higher, customized rates that will take effect after midnight Wednesday. 

Musk has refrained from criticizing Trump directly, but his dissatisfaction with the tariffs has been apparent. On Monday, he reposted a video of libertarian economist Milton Friedman’s famous discussion about the making of a pencil. 

Trump's sweeping tariffs explained

• A new 10% baseline rate and harsher “reciprocal” levies will impact dozens of countries, including key allies such as European Union members, Japan and Israel.
• Online Chinese retailers, such as Temu and Shein, are no longer exempt from tariffs, due to the closing of a trade loophole on de minimus goods. 
• A 25% tariff has been issued on foreign-made cars, which impacts roughly half of all vehicles sold in America.
• Following Trump’s “Liberation Day,” the Dow plunged more than 1,000 points over fears of an all-out trade war.

The South Africa-born tycoon also publicly expressed hope that the end result of Trump’s protectionist shift will be a zero-tariff understanding between the US and Europe. 

“At the end of the day, I hope it’s agreed that both Europe and the United States should move ideally, in my view, to a zero-tariff situation, effectively creating a free trade zone between Europe and North America,” Musk said during a video chat with Italy’s right-leaning co-ruling League party over the weekend.

“If people wish to work in Europe or wish to work in North America, they should be allowed to do so in my view,” Musk told League leader Matteo Salvini, adding that this “has certainly been my advice to the president.”

Last November, just before Trump’s electoral victory, Musk had publicly raised deep concerns about the use of tariffs to protect US industry. 

“I think you need to be careful with tariffs,” Musk told podcast titan Joe Rogan at the time. “I deal a lot with supply chain issues. Like, the global automotive supply chain for Tesla is incredibly complex. So when there are sudden changes in tariffs … it messes everything up.”

“You want to have tariffs be predictable so that tariffs can adjust their supply chain,” he added. “I think companies are more than happy to increase manufacturing in America, it’s just that you can’t do it instantly.”

Musk has enjoyed profound influence in the second Trump administration, guiding the Department of Government Efficiency (DOGE) cost-cutting crusade.

As the stark market has nosedived amid the onslaught of tariffs, Musk’s personal net worth has also sunk nearly $50 billion over the past two weeks, according to data from Bloomberg’s Billionaire Index.