It may not be binding, without a treaty ratified by Congress, like the Iran nuclear deal under Obama, but which parts are illegal?

If only the non-binding is the issue, I believe the supreme court has in the past few decades ruled treaties ratified by congress aren't binding either despite what the constitution says and that congress can undo them by not implementing them or something.

> I believe the supreme court has in the past few decades ruled treaties ratified by congress aren't binding...

This supreme court doesn't appear to be constrained by past rulings or even constitutional amendments. And 6 of 9 are on team whatever-Trump-wants.