One of the principal issues in the drafting of the Constitution was the allocation of powers between the states and the federal government. It was no surprise, then, when many of the first landmark decisions of the Supreme Court addressed that question. By and large, the federal government won those cases–otherwise, we would have a system that looks more like the EU than the US today. Since relatively few goods were moved across state lines at the time, however, the role of the federal government was inevitably quite limited until the 20th century.
Today, hardly any of the goods we consume are produced locally. That is true regardless of where you live. As a result, we need, and have, a system that regulates commercial activity primarily on a national level. The notion of allocating the regulation of the “production” of goods solely to the states would be absurd.
The Supreme Court finally got the message in the latter stages of the 1930’s. The commerce clause consequently became the constitutional vehicle by which the federal government expanded its powers, with judicial acquiescence. There were few effective checks on those powers for about 75 years. Today, however, federalism is on the Supreme Court’s agenda, and the pendulum is starting to swing back to some extent.
As a practical matter, federalism is usually an argument, not a reason; both the right and the left cite it when they are out of power, and reject it otherwise. Justice Kennedy, however, was genuinely sympathetic to federalist positions, while Roberts in particular uses them in bad faith for ideological reasons. As a result, you can expect the Supreme Court to rule consistently for Trump in disputes involving blue states, but if Bernie Sanders were somehow to get elected, red states will be making federalist arguments in the Court to block his agenda, and they are likely to have some success.