What if Napoleon managed to invade and conquers Spain and Portugal? How does this affect the War? Would the Brits invade Normandy or would the Russians continue to push into Europe?
OTL shows there was one reality in the Peninsular War: France was not going to replace the Spanish crown with a Bonaparte. Thus, there was no way for France to win the P war (as defined by taking over Portugal and Spain).
What it could have, and should have, done is take over Portugal, and kept Spain cowed. Under such circumstances, Spain is not switching sides any time soon, and all French goals are met. Britain continues to battle Spain directly (they spent money elsewhere, but aside from a couple of adventures, their main military actions were against Spain and at France through Portugal), which is another goal of France. I understand that a lot of this is hindsight, but realistically, conquest of Spain was a risk that was not necessary, using foresight, hindsight, or just closing your eyes. Sure, the prize (control of all Iberia) was a darn good one, but the consequences of not taking action was minimal compared to the consequences of failed action.
What if Napoleon managed to invade and conquers Spain and Portugal? How does this affect the War? Would the Brits invade Normandy or would the Russians continue to push into Europe?