The U.S. Supreme Court rarely weighs in on patent law, so three of its recent decisions are noteworthy--and may even be historic. In effect, they address some unintended consequences of the 1982 act of Congress that created a new patent appellate court, the Federal Circuit, which brought uniformity to patent law and reduced the likelihood that a patent would be found "invalid." Before 1982, there was always the risk that a prospective licensee would make a preëmptive strike, filing suit in a jurisdiction that routinely found patents to be "obvious" and therefore invalid. This correction spurred investments in technology and an increase in patenting to protect them. But over the past several years, the patent system's high transaction costs have threatened to offset its benefits.

Established businesses have hotly argued that the patent system needs reform. Some charge that the U.S. Patent and Trademark Office is a major problem: because patent examiners are in short supply and have an evalua­tion system that favors allowances over rejections, unworthy patents are granted. But the angriest complaints are about unscrupulous ­patent-­licensing companies--known as "trolls"--that aggressively seek licensing fees.