It's hard to tell the extent of the impact of the War of 1812 on U.S. psyche, and the eventual relationship with England; at the least, I am not knowledgeable enough to think it small, though it could be. During the 20th century, and still for many of us today, England was, and is, our strongest ally. This doesn't diminish the importance of Waterloo, but this side of the pond, the War of 1812 was significant, I believe, and with the U.S.'s eventual role in global politics, I think the War could have been more than a marginal skirmish.