Britain probably blamed the Revolution as luck, so they continued to try and assert their dominance. One way they did this was through the forts they still maintained in the Northwest Territory. Seeing Britain’s open aggression, the French and the Barbary pirates followed suit and made attacks of their own. America faced being trampled shortly after having risen. The war would prove that America didn't care how daunting the enemy; Americans would not be taken advantage of.
The only way to prove America wasn't going to allow British aggression was to declare war. Britain was stopping our ships on the high seas, kidnapping our citizens, and threatening to shell the coast. The French did their own pirating, and the Barbary pirates followed suit, taking the lead from Great Britain. By taking up arms, Americans proved they would not be downtrodden again. Defeating the British, America showed that since she doesn't allow tyranny from within, tyranny from without would not be tolerated. Words and treaties were not enough; the British wanted a war and that is what America gave