It looks insane, signaling confusion and weakness.
Bilder ’89 [Richard; October 1989; Professor of Law at the University of Wisconsin-Madison; American Journal of International Law, “Distribution of Constitutional Authority: The Role of States and Cities in Foreign Relations,” vol. 83]
The arguments for state and local governments to stay completely out of matters relating to foreign affairs include the following.
First, the vital national interest in the effective and efficient achievement of U.S. foreign relations objectives requires that other nations perceive our foreign policy as unified and coherent -- that our nation "speak with one voice." Consequently, state and local involvement in international issues, particularly if not in accord with administration policy, may undermine the conduct of U.S. foreign relations and the credibility of our negotiating posture by conveying the appearance of disagreement, confusion, uncertainty and weakness in our Government's stated foreign policy positions.
Second, state and local activities may sometimes directly impede or frustrate national foreign policy or embarrass our foreign relations by causing offense or injury to foreign nations, their citizens or their economic interests. It is inappropriate and irresponsible for particular states and localities, acting on their own and without regard to broader national public opinion or policy, to adopt measures that may result in adverse consequences for the nation as a whole.