New U.S. sanctions on Russia's two largest oil producers mark the most consequential escalation of economic pressure on Moscow since launching its full-scale invasion of Ukraine in February 2022, which signals Washington's intent to constrict the Kremlin's war financing, while testing oil market stability and Putin's capacity to endure prolonged attrition. The United States' Oct. 22 sanctions target Rosneft and Lukoil, which together produce roughly 5 million barrels per day (bpd), representing about half of Russia's total crude output and over 5% of global oil production. The two companies also export nearly 2 million bpd, representing roughly two-thirds of Russia's total crude exports. Announced by the U.S. Treasury as a direct effort to pressure Moscow into a ceasefire, the measures bar U.S. and foreign banks from financing or clearing transactions and include a 30-day wind-down period ending on Nov. 21. They build on the United States and other Western countries'...