It does not matter who started what. You are at War with Portugal by attempting to Invade Spain.
The United States cannot stand by while your agressive tactics threaten the state of Portugal.
We will break our NAP with you as soon as we can to help in the defense of Portugal, they are our Total Allies and we will defend them against you, Great Britain or any other who decided to take a pop.
If you are in any doubt of our resolve then you should know our first fleet is already in Europe, our second is on its way along with men and materials.
I must say the reports of Irelands green pastures are true, they would make suitable homes for our American citizens. We have plenty of Irish immigrants wanting to come home.