According to James Loewen, the most important cause of the War of 1812 was the desire of white Americans to push the boundaries of white settlement further into Indian country, which the British wanted to keep as a kind of buffer state between the United States and Canada.
Loewen observes that all but three textbooks make an attempt at a reasonable inquiry into the causes of the war. The others simply parrot the pretext offered at the time by the Madison Administration, that Britain had refused to show due appropriate respect to American ships and seamen.
But as Loewen points out, the British maritime laws that President Madison claimed to find so offensive, and which he blamed for causing the War of 1812, had been in force for five years without generating any trouble.
It was only when hawkish politicians from the frontier states vowed to expand the boundaries of the United States that British maritime law was invoked as a bone of contention. This despite the fact that the frontier regions of the United States were the least affected by British policy towards American shipping.
The only reasonable conclusion to be drawn from this is that the Madison Administration invoked the red herring of British maritime law as a cause of war in order to divert attention from the most important cause of the outbreak of hostilities: a radical difference in strategic vision between the British and the Americans concerning the disposal of Indian territory.