The F-35 was sold to us as an important multi billion business deal, with lots of European companies being promised to be subcontractors or technology partners;
https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning... has a good overview of how much was involved. Basically, you scratch my back, we'll scratch yours kind of deal.
In hindsight, the project was (as expected) over budget etc. I wish our government(s) had given that money to European fighter jets instead. There's a chance the US will remote disable the jets that have been put into service now, or withold service / spare parts.
