Mark Cuban mocks Trump's tariffs at Harris rally as Elon Musk tours PA

Mark Cuban on Thursday mocked Donald Trump over his sweeping tariff proposals, suggesting that the Republican presidential candidate doesn't understand his own tax ideas.

“I learned a lot about business, including how tariffs work,” the billionaire investor and former “Shark Tank” host told supporters of Democratic candidate Kamala Harris at a campaign rally in La Crosse, Wisconsin.

Trump “thinks China is paying for it,” Cuban said of the proposal to increase taxes on all imported goods from China to 60% or more.

“This is the same guy who thought Mexico would pay for the wall,” Cuban quipped, sparking laughter and cheers from the crowd.

Trump has repeatedly pointed to tariffs as a sort of panacea, arguing that high import tariffs — including a blanket tariff of up to 20% — will bring in huge revenues from abroad, finance a series of tax cuts and boost U.S. industries, all without inflation cause.

But U.S. importers are the ones paying those tariffs directly to the government, and mainstream economists say implementing Trump's plans would increase costs for Americans. For example, the Peterson Institute for International Economics found that a 20% general tariff and a 60% tariff on China would cost the typical U.S. household more than $2,600 per year.

Cuban added that he believes Trump “understood how tariffs work” back in the 1990s and 2000s.

“But I don’t know what happened to him,” Cuban said.

The appearance in Wisconsin was the first of three swing states that Cuban visited to support the vice president's bid for the White House.

According to the Harris campaign, Cuban will travel to Phoenix, Arizona, on Saturday to give a presentation on Harris' economic agenda. On Sunday he will compete with second gentleman Douglas Emhoff in Grand Rapids, Michigan.

Trump also receives local support from a well-known billionaire: Tesla and SpaceX CEO Elon Musk.

Musk was scheduled for a multi-day speaking tour of Pennsylvania on Thursday with America PAC, the super-political action committee he uses to spend tens of millions of dollars in support of Trump.

He was scheduled to host a town hall in Delaware County, Pennsylvania, on Thursday afternoon to promote absentee voting and early voting in the commonwealth, NBC News reported.

Musk announced his turnout plans shortly after Federal Election Commission filings showed he donated nearly $75 million to America PAC between July and early September alone.

Musk recently joined Trump on stage at a campaign rally near Butler, Pennsylvania, the same site of a July 13 rally where a would-be assassin nearly killed Trump and fatally shot another attendee.

Cuban's sweep of major battlegrounds, first reported by Yahoo Finance, follows his frequent praise of Harris on CNBC and in other media interviews.

Cuban has long been an outspoken critic of Trump. In a Harris campaign press conference last month, Cuban called Trump's promise of sweeping tariffs and even higher import duties against China “crazy.”

“And so to say that we're going to impose a 10%, 20%, or 60% tariff on China or any other company, any other country, is just inflationary, and that's just a tax on the American people. “This is a sales tax through and through,” Cuban said on that Sept. 24 call.