I think the EU’s best leverage on the US is to agitate that they’re going to stop buying US arms.

The US MIC has enormous influence over our government. Sales to Russia wouldn’t make up the difference; Trump would suddenly start singing a different tune.

EU countries spend something like $36Bn per year on US arms. This includes one-off sales of things like fighter jets to individual member countries, so it’s not a reliable stream (recurring contracts are only about $5.5Bn of that), but they’re purchases that happen fairly regularly - someone is always making a big purchase, every year.

Russia’s entire military budget was $65Bn in 2020. Even if they stopped spending all money on their own, native developed systems and shut all of that development down, putting all of those companies and people out of work; and even if they stopped buying from countries like N Korea and China; and even if they were able and willing to afford to make the switch to NATO standards in the middle of a conflict; and somehow came up with enough money to retool their entire military with NATO-standard weaponry… they still wouldn’t be able to make up for the losses US arms dealers - and the US government - would take in losing EU sales.

Honestly, the EU couldn’t afford it either. They’d have their own military industrial complex, but it’d have to be massively ramped up to make up for the shortfall. It’d be good for their economies, probably; lots of new domestic jobs, and new industry. But they couldn’t do it fast enough. They could build enough Typhoons, Mirages, and all of the other capability-specific planes they have demand for. And that’s just the planes.

Still, if I were the EU, I’d ignore the White House and start backroom talks with Lockheed Martin and General Dynamics executives, and threaten to ramp up domestic production and ramp down purchases, if US policy doesn’t change.