Canada

Honestly, it doesn't matter if it's possible or not. The very fact that key replacement parts of the jet can only be built in the US means that the very moment they chose not to sell those parts to Canada, the F35 is on a strict time limit before becoming the world's most expensive paperweight.

And that time limit isn't even very long. Maybe two years of normal use outside of a war, as little as a month or two during a war or any sort of foreign deployment.

We're kinda locked in for the first few planes, but despite cancellation fees, we need to replace our aging fleet with something from someone that won't throw a tantrum and erase a key component of our national defense with the swipe of a pen.