U.S. President Joe Biden is leading an effort to manipulate the oil market at a scale the world has rarely seen, embracing cartel-like tactics in an aggressive but risky attempt to undermine Russia’s war effort in Ukraine.

At the Group of Seven industrialized nations meeting this week in the Bavarian Alps, Biden has attempted to assemble an upside-down version of OPEC, the world’s most powerful oil cartel, with the goal of soothing consumers burned at the gasoline pump and, if the allies get their way, helping to speed the end of the war.

Instead of limiting supply to maximize revenues for countries selling oil, as a cartel does, Biden is trying to minimize how much one particular seller — Moscow — reaps from each barrel. He led his G7 counterparts to agree on Tuesday to a plan that would cap the price of Russian oil, as a way of driving down the revenue Russian President Vladimir Putin is deriving from his most important export.