And yet he was bold enough to gather resources for war with Russia. Napoleon, in the end it seemed, was a dumbass. If he was gonna attack Russia he could have atleast gone after St. Petersburg, he was attacking the wrong capital city.
You can do things like that when you are Napoleon I, Emperor of France.
In 1798 it was still only general Bonaparte, even if he was the toast of the revolutionary armies. I mean, Bernadotte could still challenge him for glory and political influence all on his own.
Napoleon was also a bit of a hot potato for the people in charge. A nice, limited little war in some romantically distant place was just the thing to unburden themselves of the presence in Paris of this young general, they decided.
Makes for a bit of difference.
As for the Russian campaign, Napoleon was hoping for a quick war, where the Russians would march out of Russia, line up, and be defeated. After which him and Alexander would make a treaty, the important part of which would be to attempt the financial strangulation of Britain.
It's possible the massiveness of the Grande Armée worked against Napoleon on this. Instead of showing up like good lads, the Russian armies, their commanders unable to envisage how to successfully fight such a monster, started retreating. (They felt truly ashamed of this course of action.) So Napoleon decided he had to go in and find them, which turned out to be the big mistake.
The time between the declaration of war and the capture of Moscow was only some 50 days. For an army walking there, it's a pretty speedy war. Since the objective is to find and defeat the enemy forces, if they don't retreat towards St. Petersburg, you won't be going there.
Of course, it's daft to invade Russia with no real plan, but it seems that was pretty much what Napoleon did in the summer or 1812.