George Bernard Shaw once wrote that "no question is so difficult to answer as that to which the answer is obvious." This might as well be the Supreme Court's motto as it considers KSR v. Teleflex later this month.

The case - the third significant patent case the Supremes have taken up over the past year - involves the patent law concept of "obviousness," which prevents the issuance of a patent for an invention that is so trivial it would have been obvious to create. If the differences between the invention and already-existing devices or written references, known as "prior art," are minimal, the invention will be considered obvious. Incidentally, the Court has not heard an obviousness case in 30 years.

By federal statute, a patent shall not issue if "the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art."

Thus, for instance, everyone in the tooling industry is aware of the existence of a four-pronged Phillips-head screwdriver (incidentally, Henry Phillips himself received a patent for his invention in 1936). So if a machinist one day came up with a five-pronged Phillips driver that proved marginally more useful than the original, it likely wouldn't be patentable because it would have been obvious to invent.

In a seminal 1966 case, Graham v. John Deere, the Supreme Court explained that the test of whether something is obvious is highly fact-specific and depends on multiple factors. The Court held that a patent may not issue "if the difference between the new thing and what was known before is not considered sufficiently great to warrant a patent."

The Court also cautioned against using hindsight in the obviousness determination. Many inventions that were revolutionary when they first appeared now seem almost insignificant in retrospect.

In addition, some inventions consist of nothing more than a combination of already existing parts or ideas - but they may still be patentable. For example, in U.S. v. Adams, the Court held that a certain type of battery was a non-obvious invention even though it consisted entirely of old elements already widely known.

The Court of Appeals for the Federal Circuit - the appellate court with exclusive jurisdiction over patent appeals - has built on the Supreme Court's guidance, adding certain detailed requirements to the obviousness analysis.

Under current Federal Circuit precedent, an invention that consists of a combination of already-existing parts is deemed obvious only if there is some kind of "teaching, suggestion, or motivation" to a person in the field to combine those parts. While the teaching can be implicit, it must exist in some form.

Thus, to take the screwdriver example, if a toolmaker decided to place a padded handle on a Phillips driver, the resulting invention might not be obvious - assuming that nowhere in the hardware or industrial design fields was there any teaching, suggestion, or motivation to add such a handle to a screwdriver.

Sound farfetched? This example closely mirrors the facts in KSR.

There, Teleflex held a patent on an automotive gas pedal assembly that combined adjustability with electronic throttle control ("ETC") system. Many cars are currently equipped with adjustable gas, brake, or clutch pedals that enable drivers of varying heights to move the pedals closer to or farther from themselves without having to adjust the seat.

In addition, many cars are also equipped with an electronic means of regulating the amount of gasoline sent to the engine with each tap on the accelerator. Originally, gas pedals were mechanically controlled by a network of cables. But ETC systems employ electronic sensors to more sensitively and accurately input fuel to the engine.

Teleflex's invention, by its own admission, consisted of the combination of these two already existing parts.

KSR asked the district (trial) court to invalidate the patent on obviousness grounds because a person of ordinary skill in the automotive field would have conceived of the desirability of adding an ETC to an adjustable pedal assembly. The court agreed, finding "little difference between the teachings of the prior art and claims of the patent-in-suit."

Teleflex appealed, arguing that the trial court did not properly apply the teaching-suggestion-motivation test. The Federal Circuit reversed, finding that "the district court...did not explain how suffering from the problem addressed by the [patent at issue] would have specifically motivated one skilled in the art to attach an electronic control to" the pedal assembly. (emphasis added)

In its petition (appeal) to the Supreme Court, KSR argued that the Federal Circuit has gone too far in requiring explicit findings in the teaching-suggestion-motivation test.

According to KSR, the test has migrated far afield from the Supreme Court's instruction in Graham. Rather than a "common-sense" approach to whether a combination invention would have been obvious in light of the prior art, KSR contended, the Federal Circuit requires either earlier device or reference to specifically instruct those of ordinary skill about the benefits of combining them.

Thus, to take our earlier example, unless various padding materials manufacturers or screwdriver makers - or commentators in either field - provide an explicit, detailed explanation of the desirability of such a combination, it is not obvious.

In KSR's view, such a standard makes little sense. In its petition, KSR pointed to a 2003 Federal Trade Commission study highly critical of the Federal Circuit's suggestion-teaching-motivation test. The study recommended an alternative analysis that would "ascribe to the person having ordinary skill in the art an ability to combine or modify prior art references that is consistent with the creativity and problem solving skills" possessed by such practitioners. In other words, if toolmakers are generally creative enough to want to add padding to their screwdrivers, then the invention would be obvious.

KSR also cited a report by the National Academies of Science and Engineering similarly skeptical of the Federal Circuit's approach. The report claimed that "creative people generally speaking strive to publish non-obvious information. So if it is obvious to those of skill in the art to combine references, it is unlikely that they will publish such information."

In an amicus brief supporting KSR, 24 intellectual property law professors offered several public policy reasons an unduly stringent obviousness test harms businesses and inventors alike.

They noted that the issuance of broad, weak, or "suspect" patents increases litigation burdens and raises the cost of technological advances. "Bad" patents also tax the Patent and Trademark Office and raise the cost of patent searches for other would-be inventors. This critique dovetails with the growing chorus in favor of congressional patent reform.

In short, the professors concluded, "it becomes more difficult to bring the benefits of technology to society, thus undermining the ultimate goal of patent law."

In response, Teleflex argued that the teaching-suggestion-motivation test accurately captures the spirit of Graham and offers important protections for inventors against Monday-morning quarterbacking - exactly what KSR and its supporters urge upon the Court.

Sure, Teleflex argued, it may seem obvious to combine an ETC with an adjustable gas pedal, or a padded handle with a screwdriver - now that someone has conceived of it. But at the time these inventions were patented, unless there was some reason for a practitioner to create such combinations, they were decidedly not obvious.

Teleflex also pointed to language in Graham stressing that "motivational" issues form the essence of the obviousness analysis and transcend the purely technical concerns of other aspects of patent law.

Thus, the KSR case implicates several core issues of contemporary patent law: inventors' rights, public benefits, and the efficiency of our judicial and administrative system.

In addition, several other aspects of this case are noteworthy to those who follow either the Supreme Court or the Federal Circuit.

First, in considering whether to grant certiorari, the Supreme Court asked the Solicitor General to submit briefing. A recent study by a patent law professor revealed that every time during the past five terms that the Court invited the government to file an amicus brief - 15 instances in total - the Solicitor General recommended granting cert. And in all 15 cases, the Court followed the government's guidance.

This was no exception. The Solicitor General sided with KSR and described the teaching-suggestion-motivation test as an "inflexible requirement" that "extends patent protection to non-innovative combinations of familiar elements."

In another intriguing wrinkle, one of the 24 professors who filed the amicus brief in support of the cert petition was Kimberly Moore, an accomplished and well-published intellectual property law professor at George Mason University who now sits on the Federal Circuit (she has the rare distinction of gliding through the Senate despite being nominated by President Bush). The brief was filed more than a year before Prof. Moore's nomination.

Still, as the professors themselves note in their brief, every single judge currently on the Federal Circuit has sat on a panel that has endorsed the teaching-suggestion-motivation test. It will be interesting to see future Judge Moore rulings on this issue.

Thus, there's a great deal at stake in this case - for inventors, for practitioners of patent law, for professors, and for judges.

In both of the recent patent cases decided by the Court, the Supremes reversed the rulings of the Federal Circuit. Will KSR mark a third straight reversal? There's no obvious answer to that question.

Michael M. Rosen, TCS Daily's Intellectual Property columnist, is an attorney in San Diego.