1812 is famous in military, political and cultural terms for another set of events. Events which had lasting and global impact.
With virtually all of Europe under his control and his access to adventures in the rest of the world blocked by the British navy’s virtual stranglehold on the sea, Napoleon felt himself compelled to launch a fatal war of conquest on Russia. The parallels with Hitler’s attempt to do the same are as striking as the outcomes. Both ended with annihilation of the invading armies and with Russian soldiers parading through the invaders’ capitals.
For the French, 1812 lead to the start of the disintegration of her network of forced alliances and peace treaties with Prussia’s revolt leading the way. Defeat after defeat and a savage guerilla war in the Spanish quagmire crippled the French military machine’s ability to take the initiative with masses of vital troops tied up fighting the allied armies under Wellington.
It was possibly at the moment of Napoleon’s greatest power, where Britain was bearing the overwhelming cost of the war against his dictatorship that America declared war.