They can challenge it, but only via the political process, not a legal process. Congress had been given the power to regulate interstate commerce (lest the ind

They can challenge it, but only via the political process, not a legal process. Congress had been given the power to regulate interstate commerce (lest the individual states try to do so themselves). This wasn't a problem for the first 120 years of the republic, because the government didn't have the budget to maintain a centralized bureaucracy to do too much (nor to mention that the concept of a centralized bureaucracy was born from Prussian authoritarianism that flowered in the latter half of the 19th century). The nationalistic progressivistic movements sweeping out of Europe hit America in the early 20th century, leading people to ask: "Europe has this, why can't we?" And we ended up with a central bank and income tax all within a decade. Big centralized government built on dangling strands of Constitutional safeguards.