The UN is not, yet, a foreign state. So, he skirts the language of the Constitution, while violating it's spirit.
But if he violated it's language, I don't think that *only* Congress could call him on it. Regardless of what the DoJ might say on the matter. They work for Eric Holder, who works for.. yep .. the perp.
The UN is not, yet, a foreign state.
If it is or becomes one then the US is a part of it as we are a part of the UN. I guess they best look out for other ‘foreign states’ like NATO, NAU, OAS, etc. which the US is a member of.