why is the War of 1812 sometimes called the 2nd revolution?

Answer 1

The British were at war with the French, and were attacking our shipping in order to prevent the French from conducting any kind of trade. The Americans went to war with England again in order to establish economic independence.

Answer 2

I've actually never heard it referred to as such, but it makes sense. The reason why it might be referred to as the 2nd revolution is because Britain was impressing (i.e. kidnapping) American sailors on the high seas for service into the Royal Navy and Napoleon. Combined with the fact that they were supplying the Indian peoples (especially those in the Northwest Territory) with arms for use against settlers, we declared war on 16 June 1812 with the added intention of adding Canada to our nation (which we failed miserably at).