Official government order that limits trade with a nation

Declaration of war

Explanation:

If the trade is limited to punish a nation, then it is likely an act of war.

I.E. America's cut in oil trade with Japan during WW2 because Japan allied with Germany, which led to Japan attacking America out of desperation/anger

s the president shall be commander in chief of the army and navy of the united states, and of the militia of the several states, when called into the actual service of the united states; he may require the opinion, in writing, of the principal officer in each of the executive departments. sooo yeahhh

explanation:

he believed that strong monarchies would lead to social and political stability.