Regi Move

[Napoleon]

If I use the Regi Move Poke-Power from the Regice LA...

Must I discard 2 cards?
Does the power fail if the opposing Pokemon is unevolved?

e.g.
I only want to discard one card, but I won't move the opponent's Pokemon
I want to use the power but my opponent has Machamp active. Can I still discard the cards?

 

[PokePop]

In order to use the Power you must discard two cards.
You can do this even if the opponent's active is unevolved.
If that is the case, then the switch won't happen.

In your example, you would still need to discard two cards.