[MinorTom]

> - Change their constitution

That isn't possible

> - Change their interpretation of their constitution

The BVerfG tries really hard to interpret the constitution in a way in line with EU regulations, but it reserves the right not to (if they're "ultra vires" - beyond their power).

> - Leave the EU

Not going to happen.

> It's a basic principle of participation in a Union.

Note that the supremacy of the German constitution over EU law was well known at the time of signing the relevant treaties and all parties agreed to proceed anyway.

> Germany's or Poland's case is the same as if a State of the US decided that some federal law or the US constitution doesn't apply [...]

The EU is not a nation state.