Politico’s Josh Gerstein has one of the more comprehensive — and more entertaining — run-downs of the case law that the Supreme Court will rely on when it opens oral arguments on the health reform law Monday:

No previous Supreme Court case is a perfect match for the Obama health care law, but a 70-year-old ruling about an Ohio wheat farmer comes closest.

Roscoe Filburn fought a federal law that imposed a penalty on every bushel of wheat he grew above a certain quota. Filburn said all of the extra grain was being consumed on his farm, but the court ruled that the federal government could regulate his crop because every bushel he grew was one he wouldn’t buy from others.

Even “if we assume that it is never marketed, it supplies a need of the man who grew it which would otherwise be reflected by purchases in the open market,” Justice Robert Jackson wrote for a unanimous court in Wickard v. Filburn. “Home-grown wheat in this sense competes with wheat in commerce.”

The two well-known conservative judges who upheld Obama’s health care law, appeals court judges Jeffrey Sutton and Laurence Silberman, put great weight on the wheat case.

For more on how pot and guns factor in, read Gerstein’s full story here. And be sure to check out New York Times’ Linda Greenhouse on why she expects the Supreme Court to uphold the law.