The question is celebrated: if HaShem hardened Pharaoh's heart, then it was HaShem who made Pharaoh refuse to let the Jews go, not Pharaoh himself. How, then, could it be right to punish Pharaoh and his people for a series of decisions that were not made freely by Pharaoh himself?
Amidst his essay on this topic, the Ramban (1194-1270) writes that the hardening of Pharaoh's heart was a fulfillment of the verse in Proverbs (21:1) "Like streams of water is the heart of a king in the hand of G-d; wherever He wishes, so He directs it." Just as a farmer might direct the flow of a stream to irrigate his fields, so G-d directs the heart of the king. While regular people may always be granted free will, world leaders may be different. Whether that is because of the immense impact of the leader's decisions and therefore the potential recklessness that could ensue from their total free choice (Ralbag,) or so that G-d can direct the course of history (Ramchal,) the reality stands. No matter our individual political stances, we can rest assured that at the end of the day, historical decisions can only be made with G-d's direction.
Rabbi Michael Macks will be contributing weekly divrei torah as he is able