The cap and tax’s building code is a direct assault on the state’s “exclusive” power over real estate and property law. First, a little background.
By today’s standards, one can make an irrefutable argument that Constitution gives the federal legislature the power to pass local parking regulations: Automobiles travel interstate. People drive them to stores to buy merchandise which itself has traveled interstate. Since the federal legislature has the power to regulate anything that directly or indirectly affects interstate commerce and since parking affects interstate commerce, the federal legislature can pass exclusive parking regulations.
Any law made in pursuant to the Constitution is the “supreme law of the land” and “judges in every state are bound thereby” irrespective of the constitution or laws of that state. In other words, if the Constitution empowers the federal legislature to pass some law, it is the only law.
There seems to be two conditions for nullification or preemption of state law by federal law. First, the federal law must be authorized by the constitution. Second, the state law must conflict with the federal law.
Given the expansive interpretation of the interstate commerce clause (Wickard v. Filburn), few federal laws will be found to exceed it. These days, nobody is going to spend time or money arguing that such-and-such federal law exceeds the delegated power of the commerce clause.
The only practical rebuttal to the federal parking regulations above is that states have historically regulated parking. Courts sympathetic to the principles of federalism have developed the clear statement doctrine. It says that if congress intends to alter the historical relations between the states and the central government, it must say so clearly and unambiguously.
However, the purpose of the clear statement doctrine is to divine the intent of congress vis a vis state laws, not to determine whether congress has the constitutional power — that is assumed. In other words, a question arising about the scope of preemption of the federal parking regulations can be resolved by congress clearly and unambiguously stating its intent to preempt all other parking regulations.
If congress has the constitutional power to pass a law, it has the power to preempt state laws and constitutions. If it has power to preempt state laws and constitutions, the state never had that power in the first place. Until the time congress preempts the state law, the states have been acting by the authority granted it not by its people through the state constitution but by the forbearance of federal legislators – congress is letting the states regulate. In other words, the people delegated power to the federal government which temporarily delegated it to the state governments. The federal government may revoke its temporary delegation to the states at its will.
If the federal legislature preempted all state laws and constitutions to the extent of the power purportedly granted it by the commerce clause, it is hard to see any authority remaining in the state. This general preemption leads to absurd but necessary conclusions.
Consider criminal law. States have always prosecuted and punished armed robberies. The federal Hobbs Act is a statute allowing federal prosecution of armed robberies affecting interstate commerce. Since all armed robberies affect interstate commerce, all armed robberies are violations of the Hobbs Act.* (One case cited in the US Attorney’s manual was found to affect interstate commerce because the stolen money was going to be used to buy goods from interstate commerce!)
If the federal congress can punish all armed robberies, it can expressly preempt all existing state armed robbery laws. If it can preempt all state armed robbery laws, states never had the power to punish them in the first place. That states have prosecuted these crimes up till now is because the federal congress lets them.
The same argument goes for federal building codes. If the federal government has the ability to pass federal building codes now, it has always had it. Of course, they will argue that they are not preempting the whole building code just a part of it. But I hope it is clear that asserting that the federal legislature can preempt part of the local building code is an argument that it can preempt all of it. It is an assertion that the state never really had the power in the first place.
*The current ability to select state or federal law for prosecution raises a host of issues which will not be addressed here.