Final answer:
President Madison declared war on Britain due to their violation of the 1783 Treaty of Paris through their policy of impressment.
Step-by-step explanation:
President Madison declared war on Britain for several reasons, but the reason that was a violation of the 1783 Treaty of Paris was Britain's policy of impressment. Impressment refers to the practice of forcing American sailors into service in the British navy. This violated the treaty's provision that the British would respect American sovereignty and not interfere with American citizens.
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