Because Napoleon didn't want to depose the Tsar, much less to conquer Russia, he just wanted to impose his (Napoleon's) will on the Tsar and on Russia as a whole when it came to strictly imposing the Continental Blockade against the British. A heavily defeated Russia wouldn't have helped him into achieving that.
> Because Napoleon didn't want to depose the Tsar, much less to conquer Russia... A heavily defeated Russia wouldn't have helped him into achieving [the blockade of Britain].
You think a heavily defeated Napoleon would help him a lot in that matter? Realistically, there was no third option, going in guaranteed than one of them would be heavily defeated.
At that point in time, Napoleon was in command of the largest and most heavily armed military force in history. And he assembled it to go beg the Tsar to blockade a third country? It doesn't make any sense.
