A small cost (of other peoples money) to try and buy a meager gain in approval.
Im sure the sea lawyers will come out of the woodworking to provide some commentary, but all I can think is "how in the world is this legal?"
The government cannot legally keep surpluses.
The social security administration got around this (up to 2020-ish) by purchasing U.S. treasuries with its surplus (i.e., 'intra-governmental debt,' the only thing keeping social security solvent right now).
If tariffs result in a net positive in whatever financial bucket they are allocated, the President is obligated to either give it back or buy government bonds with it to pay it back later with interest. It doesn't matter if the
overall budget is negative, it matters whether that 'pot' is positive or negative.
And of course tariffs raised on executive orders have yielded more revenue than required by statute. So the tariff 'pot' is overflowed and Trump can't tell Scott Bessent to buyback a whole bunch of government bonds - the physical instrument that constitutes our debt - prior to maturation. The other inconvenient factor is that it would require the other party, US banks, to willingly sell them prior to obtaining their full yield. And they won't because of fractional reserve banking and how they calculated their risk for giving loans.
Trump is making this seem like a novel concept that only he can do, because that's his MO, but what he's doing is quite ordinary given the legal constraints of what he can do with extra revenue. Because when his fiscal policy advisors told him "no, you can't cut all these income and corporate taxes and then pay for it with tariffs due to a bunch of statutory regulations," Trump responded by throwing a tantrum and treating them like idiots until he realized they were right.
His gambit is that the Supreme Court won't call foul on his executive orders that increase tariffs and make him pay it back to the impacted nations... or if they do, the GOP led Congress will cave and pass a stimulus bill to support his policies.