It's "The War of '12" -- note the apostrophe, as it refers to "the War of 1812".
This most probably refers to what the British call the American War of 1812, fought between Britain and the US from 1812 to 1815. The causes are very difficult and complex, but basically Britain didn't want the US to trade with France. This is because at the time Britain was also at war with Napoleon of France. (British historians talk about the "American War of 1812" to make it clear that they're not talking about the war with France.)
War of 1812 - Wikipedia, the free encyclopedia