Germany is free to exit NATO and close Ramstein. I believe it only requires a 1-2 year notice period.

The defense budget required to operate without US assistance is another matter entirely; you’re looking at doubling existing spending, plus hundreds of billions in one-off procurement costs — and that assumes ongoing access to US weapons systems.

The US subsidizes the massive weapons development programs you currently rely on; cost sharing agreements and unit purchases do not come close to offsetting the full sunk R&D costs the US covers.

Replacing those weapons programs, and the existing US industrial base and supply chain they depend on, would run into the trillions of dollars.

Just the R&D portion of the US defense budget is $150B a year — the entire EU’s aggregate defense R&D spending is only ~€15B/year.

A truly independent EU that did not depend on the US for its security would be a very different place.