Notably, Trump announced the move during a speech in Michigan, where he spoke before the Detroit Economic Club. Michigan is the United States’s auto manufacturing hub. The rollout was similar to how he announced his plan to end taxes on tips during a visit to service industry-heavy Nevada.

“Today I am also announcing that as part of our tax cuts, we will make interest on car loans fully deductible,” Trump said to cheers.

The former president, who is vying for another term in office against Vice President Kamala Harris, announced the move would “revolutionize” the auto industry. He said someone in the crowd had told him it was as novel an idea as the invention of paper clips.

During his speech, Trump highlighted how costly it has become to own a car in the U.S. amid years of inflation that is too high.

“This will stimulate massive domestic auto production and make car ownership dramatically more affordable for millions and millions of working American families,” Trump said. “This is a phenomenal thing if I do say so myself.”

The proposal would be expensive for the federal government and would further add to the debt and deficits, although it is not immediately clear exactly how much such a plan would cost.

Despite the government’s rising debt, both candidates have pitched ideas that would, on balance, add to the national debt, according to analysts. This week, the Committee for a Responsible Federal Budget released a new report that showed the fiscal footprints of the Trump and Harris plans.

The Harris economic plan would likely add $3.5 trillion to the national debt, while Trump’s would add $7.5 trillion, according to the report. Both candidates have disputed those calculations.