I think the big problem with that is the issue of slavery, the Missiouri compromise already said no slavery above this line and if we took more land above this line don't think it would help some of the biggest warhawks.
Napoleon's army
Also, another thing to think about is that the majority of Napoleon's army is playing in central Europe at this time. Having defeated General Mack and getting ready to try and close down the Austrians and Russians.