I've seen it done and one of our largest customers is moving a massive production line from one country to another it as we speak. Large, multinational corporations shift production from one country to another frequently and it is really not the obstacle that it once was, even for somewhat complex manufacturing operations. Many of the large companies already have operations in the US, so they would not be starting from scratch with their workforce, but rather moving workers from other facilities to assist with the transition.
European wages are higher than some areas of the US, so a move to the US may not result in increased labor costs. A 25% tariff is a huge incentive for foreign companies to look at manufacturing in the US.