The government's prosecutorial powers are vast and, more importantly, flexible. Many crimes or regulatory violations can be prosecuted because they involve "interstate commerce" in some way.
Article 1, Section 8, Clause 3 of the US Constitution gives Congress the exclusive authority to manage commerce between the states, with foreign nations, and Indian tribes. The US Supreme Court (SCOTUS) has upheld decisions based on this clause for violations that otherwise had no bearing on "interstate commerce." Note: Some of the decisions were the right thing to do, but not based on an expansive definition of "commerce."
One landmark case involved an Atlanta hotel that refused to rent rooms to blacks. The court ruled that this practice interfered with interstate commerce and that the owners could be prosecuted under federal law. Another decision involved a California law that prosecuted anyone who brought an out-of-state "indigent" into the state. The state law was overturned by the SCOTUS because it affected "interstate commerce."
Although the SCOTUS in recent years has shown a tendency to interpret the law so as to actually involve commerce that is interstate, the precedent has already been set. An expansive interpretation of a law or regulation is the prerogative of the government.
Recently there has been a flood of legislation introduced to fight "global warming." (Read 80% of my previous posts if you want to know my opinion on global warming.) Polar bears have been put on the "threatened species" list, not because there's a shortage of polar bears, but because of the threat that global warming supposedly poses to their habitat.
Now there's a story headlined "Obesity Contributes to Global Warming." Given the broad and spreading interpretation of laws shown previously by the courts, it's not unreasonable to anticipate future prosecution of criminal charges against people the government deems overweight, because of their violation of "global warming" laws.
As with the "interstate commerce" clause, global warming laws can be expanded to prosecute any type of offense, based on what someone, somewhere says contributes to global warming. Politicians (including judges) pander to public opinion constantly, and lack the moral courage to resist the latest political fad whether it makes sense or not.
The global warming theorists have inserted themselves like ticks under the skin of politicians. The regulation of exhaust emissions by automobiles is the least of our worries these days. Soon, Americans will have every aspect of their lives controlled because of craven politicians and global warming profiteers.