Constitutional Law Question: Executive agreements and orders Forum

[Norwood]

What are the limitations of executive agreements?

If Congress fails to enact a statute to allow a president to seize steel factories in time of an emergency (like Youngstown), can the president enter into an executive agreement (not a treaty) with another country in order to authorize seizures? In other words, can the president use an executive agreement as a way to get something done that Congress has not approved?

Also, how do you analyze an executive order issue? How do you determine whether the order was constitutional or not?