No, but as soon as you start asking questions like "is X country really worth it compared to nuclear war?" then the deterrent has failed.
A loss in Ukraine means every non-NATO state in the region either gets nuclear armed up, or gets annexed.
The expectation that the result of "letting it happen" would also be cheap gas is laughable: if someone's willing to trade away their morals and a country for something you sell them, then you already know it's underpriced.