Elon Musk's tariff rift with Trump's top trade advisor is getting ugly

"A PhD in Econ from Harvard is a bad thing, not a good thing," Elon Musk said of Peter Navarro's academic qualifications.

Andrew Harnik via Getty Images

• Elon Musk doesn't agree with Peter Navarro's views on tariffs.
• "A PhD in Econ from Harvard is a bad thing, not a good thing," Musk said of Navarro's background.
• Musk said he wants a "free trade zone" between Europe and the US.

Elon Musk, one of President Donald Trump's biggest supporters, has been locking horns with Trump's top trade advisor...