Farmers plant seeds. Where do they get the seeds? Lots of places. Their own crops. Farmer Crawford up the road. Bean sellers. Monsanto. And so on.

What if the seeds use a technique that someone — Monsanto, say — has taken out a patent on? Can you use seeds from a crop that you or someone else grew with Monsanto seeds to make a new crop? Or would that infringe those nice Monsanto people's patent?

It would do the infringement thing. So a 9-0 Supreme Court held today in Bowman v. Monsanto Co., No. 11-796 (U.S. May 13, 2013).

Justice Kagan wrote for the Court. She noted that buying a product that uses a patentee's invention has never given the purchaser a right to make copies of the product. Sure, as a matter of patent law, the buyer can use the one he lawfully acquired any way he wants. He can run it, sell it, lend it, dress it in doll clothes, burn it, chop it into thousands of little pieces, worship it, bury it in his back yard, or say ugly things to it. We call that the "patent exhaustion" doctrine. But letting him copy it would give him a right that belongs only to the patent-holder.

Vernon Bowman, an Indiana farmer, had gotten some of Monsanto's Roundup Ready soybean seeds from a vendor (grain elevator) and used them to plant several crops. Monsanto sued him for patent infringement and won a judgment for $85,000. Farmer Bowman asked the Supreme Court to overturn the judgment, arguing that a mean old company like Monsanto shouldn't have the right to profit from generation after generation of Roundup Ready soybeans, over the 20 or so year life of the patent. Monsanto's entitlement to charge royalties, he urged, should end when it makes the first sale of the seeds, after which sale it will have exhausted its patent rights.

That approach didn't sell.

Neither did his "seeds-are-special argument: that soybeans naturally 'self-replicate or 'sprout' unless stored in a controlled manner,' and thus 'it was the planted soybean, not Bowman' himself, that made replicas of Monsanto's patented invention." Id. at 9. Deeming the point a "blame-the-bean defense", Justice Kagan observed that Bowman "devised and executed a novel way to harvest crops from Roundup Ready seeds without paying the usual premium" and grew "eight successive soybean crops" as a result. Id. "In all this, the bean surely figured. But it was Bowman, and not the bean, who controlled the reproduction (unto the eighth generation) of Monsanto's patented invention." Id. at 10.

The Court cautioned that its holding may not cover all things that make copies of themselves — such as things whose self-replication "might occur outside the purchaser's control" or "might be a necessary but incidental step in using the item for another purpose", as in some computer software programs. Id.