Trump's trade rhetoric may not be all bluster. He needs mammoth tariffs to pay for everything else he wants.

Donald Trump is making dramatic new tariff pronouncements almost daily that one could be tempted to dismiss as bluster, but it is increasingly clear that he needs a titanic level of duties to fulfill the promises of his second-term agenda.

"I'm gonna put a 100, 200, 2000% tariff," he proclaimed last Tuesday in Chicago on the subject of auto imports, promising "the highest tariff in history."

It was at that event at the Economic Club of Chicago where he also floated the idea of across-the-board tariffs as high as 50% in order to immediately force companies to relocate.

But a significant fraction of that bravado may actually be needed if he wins in November and wants to pay for everything else he wants.

"There's actually a logic to the tariffs for his other policy goals," said Brendan Duke, a left-leaning economist at the Center for American Progress who has studied the potential economic effects of the tariffs.

"It helps him with his math problem" on issues like paying for his wide array of tax cut promises, he added.

TOPSHOT - Former US President and Republican presidential candidate Donald Trump arrives for a town hall event at the Crown Complex in Fayetteville, North Carolina, on October 4, 2024. (Photo by Logan Cyrus / AFP) (Photo by LOGAN CYRUS/AFP via Getty Images)
Former President and Republican presidential candidate Donald Trump arrives for a town hall event in North Carolina on Oct. 4. (LOGAN CYRUS/AFP via Getty Images) · LOGAN CYRUS via Getty Images

Indeed, a detailed analysis of Trump's plans from the nonpartisan Committee for a Responsible Federal Budget found that one of the only sizable offsets to his over $10 trillion in campaign trail promises is tariffs — which are projected to raise about $2.7 trillion.

And in the report's rosiest possibility — with Trump's tariffs raising more and his programs costing less than many expect — a Trump agenda adds a relatively manageable $1.45 trillion to the national debt because of that tariff revenue. More likely is a shortfall in the neighborhood of $7.5 trillion.

All scenarios point to a likelihood that Trump may have little to no motivation to veer away from tariffs in office.

"People think he's a dealmaker," added Mary Lovely, a senior fellow at the Peterson Institute for International Economics who has done her own deep dives on the economic ripples of renewed trade tensions.

Lovely adds that some common assumptions — such as that Trump is using bluster as a negotiating tactic or that he doesn't really mean much of what he says — rely on a "really revisionist history" of how Trump has tended to approach trade issues.

Read more: What the 2024 campaign means for your wallet: The Yahoo Finance guide to the presidential election

Why tariffs are 'most important element' of Trump's plans

Tariffs are, of course, taxes that are paid by importers at points of entry, with the additional costs levied on these companies often passed on to consumers in the US.