$5,000 payments to roughly 245 million U.S. adults would cost about $1.25 trillion, far above the $125 billion in annual tariff revenue Vice President JD Vance said would fund the plan.
Erica York of the Tax Foundation said the gap would likely be financed with new borrowing, pushing the federal deficit to about $3 trillion from roughly $1.8 trillion and unsettling Treasury investors.
Economists said the one-time cash infusion would boost consumer spending and risk reviving inflation, with August CPI due Friday expected to show prices still rising 3.3% annually versus the Fed's 2% target.
Fiscal critics said the proposal is dangerous with U.S. debt above $40 trillion and interest costs already exceeding defense or Medicare, while higher Treasury yields could raise mortgage, auto and personal loan costs.
Trump floated the dividend at the Republican National Committee's summer meeting as a middle-class measure ahead of the midterms, though Wall Street expects Congress would have to approve it and may resist.