The war of 1812, also known as the Inconclusive Revolution, is called the second American Revolution because while in the first revolution we fought to become our own country, this second revolution asserted our American rights, and gave Americans the opportunity to show their true colors, their courage and the message of "Do not thread on us" when it comes to our rights.
The Peace Treaty of 1783 marked the end of the first American Revolution. At the time, there was continuous expansion of the territories, and the United State still had territories belonging to both the French and the Spanish. In the same token, the new Americans were conducting trades with nations in Europe, and were building its military with the aid of foreign consultants. It was a fine line between ethics and irony, but they did what they had to do.
On the other hand, Europe did not share the feeling of self that the Americans felt, and still sort of treated them as colonists. Hence, Britain could have bullied the united states into following certain rules that would block their development as a country.
One of those rules was trade. Britain, starting a fight with France that would be known as the French Revolution (1793-1815) forbade the United States from trading or doing any kind of communication with France. This was a heavy thing to do- when u think about it, people in the ranks of Benjamin Franklin had a long-established and solid relationship in the Parisian community as an ambassador. How could we stop now?
Hence, the United States under the command of James Madison declared war on Britain in 1812, and took the Declaration of Independence as its guidon. It was the first manifestation of war with Britain after 20 years of battling back and forth for our newly-created rights.