The outgoing Biden administration threw the proverbial kitchen sink at Russia’s energy sector on Friday with a sweeping slate of sanctions meant to curtail Moscow’s still-resilient energy earnings and potentially weaken its war-making power in a critical year for Ukraine’s survival.

The measures announced Friday do all and more that the Biden administration had shied away from since the start of the full-scale Russian invasion of Ukraine in 2022: going after the production, distribution, sales, and financing of Russian oil and gas, long the mainstay of Moscow’s war chest and still the most vulnerable part of its creaky economy.

The moves include sanctions on two Russian oil majors, Gazprom Neft and Surgutneftegas, as well as more than 180 shadow fleet tankers, natural gas producers, energy traders, and oil field service providers.

“Russia is now in the penalty box,” said a senior administration official who spoke on background under conditions set by the White House.

Senior administration officials expect that the new measures will cost Russia billions of dollars a month in foregone energy revenues—no small achievement when the Kremlin banks on the order of about $20 billion a month by fueling the world at war. The idea is that Russia is going to now have to seriously choose not between guns and butter but between oil tankers and military tanks.

“Today’s actions build on recent steps that reinforce an economic trajectory along which Russia will face hard choices,” U.S. Deputy National Security Advisor Daleep Singh said in a statement. Singh described the measures as the “most significant sanctions yet” on Russia’s energy sector.

The question of why the White House decided to make these moves now is both easy to answer and surprising. For years, President Joe Biden has avoided taking the necessary and hard steps to fully go after Russia’s cash cow because that would have meant higher oil prices (and gas prices) and higher inflation for Americans. That was a particular concern during the 2022 midterm elections and especially in the recently concluded presidential contest. That is not a concern for the Biden White House now.

Officially, the White House says it is unleashing the kraken now because oil markets are relaxed and the costs will be bearable. Indeed, benchmark global crude prices have been languishing in the $70 per barrel range, which gives the administration and the United States plenty of room to run before worrying about triple digits.

Unofficially, the Biden White House is packing boxes, and this slate of sanctions is a way to kneecap Russia before handing off control to the incoming Trump administration. Given the ambivalence shown by President-elect Donald Trump and many of his officials to continue U.S. support for Ukraine, aggressive action now to further constrain Russia’s war chest gives Ukraine one last lifeline that might have not materialized otherwise. Given the stakes for Ukraine, Europe, and ultimately for the United States, buying time in 2025 makes sense.

But Friday’s measures aren’t a restraint on the incoming administration or a Parthian shot but quite the opposite.

“I view it as a gift to the Trump administration—Biden is doing the dirty work, giving the next administration more leverage to get [Russian President Vladimir] Putin to the table,” said Edward Fishman, a former senior U.S. sanctions official now at the Center on Global Energy Policy at Columbia University. “The Russian economy is already bad, so this gives the incoming administration a lot more leverage over Russia without starting on the wrong foot.”

Even those countries that might be expected to bristle at restrictions on Russian oil trade—China, India, and Turkey have outdone themselves by snapping up cheap Russian crude oil and oil products during the war—have little to fear from the latest U.S. moves. Reuters reported this week that a major Chinese port had already moved to ban U.S.-sanctioned oil tankers. India has even less to fear because the more untouchable Russia’s oil exports become, the cheaper they potentially are.

“Traders love this: ‘You guys are toxic. I need a bigger discount.’ Anybody who understands oil trading understands that India has been one of our best assets in constraining Russian oil revenue, because they can demand big discounts,” said Craig Kennedy, an expert on Russia’s energy sector at Harvard University’s Davis Center for Russian and Eurasian Studies. “India’s constantly been looking for pretexts for deeper discounts, and here we have it.”

The nitty gritty of the latest U.S. measures is where things get interesting. They go soup-to-nuts on all aspects of the Russian energy trade, which even three years into war brings in about $665 million a day to Putin’s coffers. The good news is that before the war, that was closer to $1 billion a day. The bad news is that for the last two years, sanctions have hardly budged those Russian revenues. What the latest sanctions target is everything. Much of the attention is on the designation of 183 Russian tankers, since the whole point of Russia’s sanctions-skirting exercise for the last two years has hinged on a shadow fleet of oil tankers that are entirely outside the remit of Western whipsticks.

Russia can’t trade energy much these days except by sea, so tankers are ground zero in this fight.

“Sanctioning 183 vessels will be a huge hit to Russia’s seaborne crude oil exports—it will be really huge,” said Petras Katinas of the Finland-based Centre for Research on Energy and Clean Air (CREA), where he tabulates Russian fossil fuel earnings.

Utilizing the dominance of the dollar, Biden administration officials now expect that ports and insurance companies will balk at doing business with the tankers, fearful that they may too find themselves in the crosshairs of secondary sanctions, which could cut off access to U.S. financial institutions. The preemptive ban by China’s Shandong Port Group this week spoke volumes.

Russia’s shadow fleet includes both officially Russian-flagged vessels that have fled Western insurers and a greater host of aged ships bought on the sly to ferry illicit goods. Together, that fleet carries more than 80 percent of Russia’s seaborne oil exports, according to CREA. U.S. sanctions, as have been levied piecemeal in the past, have kept those ships idling, cutting their oil transport by more than 90 percent. With the new steps, that could be a billion dollars monthly gone right there, if not more.

But the ultimate goal of curtailing what effectively amounts to between one-third and one-half of the active Russian shadow fleet is not to chase those ships from the sea entirely or to remove those barrels of Russian oil from the market. Rather, it is to herd those illicit vessels back into the confines of the Western-led, -insured, and -regulated maritime market, which includes a price cap on Russian oil that, at $60 a barrel, remains lower than what some rogue traders can still get.

“This is a long overdue step in terms of making the oil price cap binding,” Fishman said. Russia can either forgo shipping oil (and lose money) or ship oil through regulated tankers (and lose money). “This is an attempt to put real teeth into the price cap,” he said.

Depending on whom you talk to, each and every bit of the latest sanctions package is especially powerful. For Fishman, it is the United States going after two of Russia’s five major oil producers with straight-up sanctions that could potentially remove up to 2 million barrels a day of oil from global markets.

“We have not ever seen blocking sanctions on a Russian oil company directly. This is more than we ever did since 2014,” when Russia first invaded Ukraine, he added.

For Kennedy, it’s the future of Russia’s tired oil fields: The restrictions on oil field services companies mean that the Kremlin will be hard-pressed to squeeze more oil out of old fields that require world-class expertise to manage geriatric reservoirs, aided even during the war and sanctions years by Western firms such as SLB.

“Maybe not tomorrow, but they’ll lose access to the capabilities, and that will make it riskier and costlier to maintain current production levels,” Kennedy said.

And there are additional restrictions on Russian liquefied natural gas exports, which have been a life vest for the Russian gas industry and one rare growth area, especially in exports to Europe. The U.S. State Department went after a couple of minor Russian LNG projects and continued pressure on a marquee Arctic LNG project, all of which will make Russian tanked gas less appealing and U.S. natural gas exports even more so. That is likely music to Trump’s ears.

Senior administration officials fully expect that Russia will try to evade the new sanctions. Following the 2022 invasion, Russia became the most sanctioned country in the world, with more than 16,000 people and companies subject to a patchwork of international sanctions and export control orders intended to deprive it of the resources and technology to fuel its defense industrial base.

These measures have forced Moscow to seek out new and cumbersome routes to sell its energy and acquire advanced technology. This has come at a steep cost but does not appear to have persuaded Putin to climb down from his maximalist aims of subjugating Ukraine.

The senior administration official compared U.S. sanctions to sand being poured into the gears of the Russian war machine.

The ultimate point of the belated sanctions, like the belated arms deliveries or the belated lifting of targeting restrictions, is to make it harder for Putin to continue waging a war on Ukraine that has cost him hundreds of billions of dollars and hundreds of thousands of men.

“For every tanker they have to buy, that’s fewer tanks they can buy for their war of choice in Ukraine,” a second senior administration official said ahead of the announcement.

Russia remains nonplussed by the latest moves, as one does with a currency measured in wheelbarrows and interest rates in double digits.

“Some manage to leave a mark on history, while others only manage to leave a mark,” Russian Foreign Ministry spokesperson Maria Zakharova said in response to Biden’s new sanctions.