Gore Vidal is fond of saying that we live in the United States of Amnesia. Studs Turkel has corrected Vidal by saying that things are far worse than that: we live in the United States of Alzheimer's. For evidence of this, we need go no farther than Canada.
One doesn't get to watch a Canadian being pompous very often.
The War of 1812 huh? I would guess that about 30% of Americans have a clue of what that was other than that it was some kind of war that occurred around 1812 or so. Of those people, probably half know little more than a song about how Andrew Jackson won the Battle of New Orleans. Another famous song to come from that war was the Star Spangled Banner.
As it turns out, the war started when the US declared war on the English and promptly invaded Canada. Wave after wave of invading forces was somehow repulsed by the outnumbered Canadians. I'm pretty sure that their success came because of the support of Benedict Arnold's ghost and maybe some gargoyles. The war ended when the US basically got tired of fighting and declared peace. Weeks after peace was declared, Jackson marched on New Orleans and won his famous victory over the British.
To be fair, the Americans did have some legitimate grievances against the British. The English had placed various trade restrictions on American cargo because of their war with France. American sailors were being conscripted into the English navy. Oh, and worst of all, the English were helping the Native Americans to defend themselves against US expansionism. Those BASTARDS! Regardless of the "legitimate grievances" the US claimed led to war, I'm pretty sure that the peace treaty didn't resolve any issues that couldn't have been smooth over by a little diplomacy in the first place. Also, in defense of Jackson, he apparently wasn't aware that a peace treaty had been signed when he attacked the Big Easy.
Point is, the war was basically a fairly unsuccessful attempt at territorial expansion by the US. It did have a huge impact on establishing the national identity of the United States which previously thought of itself as merely a united group of separate states. Some scholars (I'm referring mainly to Walter Borneman's book "1812: The War that Forged a Nation") even say that this tension between the states and the new national identity established by the War of 1812 led directly to the Civil War.