The United States trade deficit has been reduced by 78% because of the tariffs being charged to other companies and countries.

For

Treasury/Tariff receipts rose ~78% in a recent period, which some reports (NPR) note and could be conflated with a claim about the deficit. (NPR: “Trump tariff revenue soars 78%.”) A policy analysis (WSJ/White House Office of Trade & Manufacturing Policy PDF) shows that mirroring partners' tariffs could, in some bilateral scenarios, produce very large reductions in that bilateral deficit (an example cited an 88% bilateral reduction with India), which might be cited to imply large overall effects.

Against

FactCheck.org reports that claims of a roughly 77–78% reduction in the U.S. trade deficit are overstated and rely on selective comparisons; the site found the president’s claim exaggerated the actual change. (FactCheck.org: “Trump's Selective Comparison Overstates Trade Deficit Decline”) NPR and other reporting explain tariffs are paid to the U.S. government by importers and often passed to U.S. companies/consumers, not directly charged to other countries or firms abroad, undermining the claim that other countries were directly paying tariffs that reduced the trade deficit. (NPR: “Everything to know about Trump's tariff letters”) The broader empirical and analytic record shows tariffs do not mechanically or solely drive large reductions in the overall trade deficit: the WSJ/OTMP analysis estimates roughly a 9–10% reduction in the total U.S. goods deficit in a full-world scenario, and Reuters reporting shows past large tariff episodes (2018) coincided with rising goods deficits. (WSJ PDF; Reuters 2018)