Top Democrats are demanding major banks and ports preserve records related to Russian diesel imports, anticipating congressional investigations if they regain control of Congress. This inquiry extends beyond the White House to major corporations. The demand follows President Trump's agreement with Moscow to bring Russian exports to U.S. markets, enabled by a Treasury Department sanctions waiver. Lawmakers argue this arrangement violates a 2022 law banning Russian oil and gas imports and raises national security concerns by financing Russia's war in Ukraine. The Treasury Department, however, maintains the agreement is legal. The letter, signed by several powerful Democratic senators and representatives poised for committee leadership, urges banks and port authorities not to facilitate any Russian diesel transactions, either for U.S. import or for other markets under the sanctions waiver. They specifically request preservation of contracts, shipping documents, vessel records, and communications with suppliers, intermediaries, and U.S. government officials. Recipients are asked to confirm record preservation and provide details of any potential or actual Russian diesel transactions by Wednesday. While reports indicate some tankers have signaled U.S. destinations, it remains uncertain how much Russian diesel, if any, will ultimately reach American shores. This move signals a significant push to scrutinize the Trump administration's dealings with Russia.