It has never been the case that one party was for centralization and one was for decentralization. Neither of these are goals. Both are instead methods of achieving goals. Both parties will use claims of federalism when they want to oppose federal policy they don't like and have done so for decades and decades.
Sure, that seems to be what drives the two parties flipping and it seems to be happening now. While your team is in charge you like federal powers, when the other team is in charge you like state powers.
It is generally true, though, that one of the two parties is for decentralization at any given point in time.
I don’t know about “parties” but political movements absolutely are divided by centralization (or not). Collectivism is literally the centralization of wealth.
