The entire clumsy apparatus of the American judicial system is built to shake clean facts out of hesitant individuals. Judges hear testimony, lawyers argue, and juries sit, weighing evidence as each tries to arrive at a simple bare-bones truth. As a job-creation program, the byzantine extravaganza is a marvel of innovation and sustainable growth, but as an efficient way to get to the heart of the matter, well, don’t ask. It’s still Jarndyce v. Jarndyce, 150 years on. How much simpler (and cheaper) it might be if only we could distinguish the truth tellers from the liars. Then an entire trial could be boiled down to asking a single person if he committed the crime.

“Truth serum” once showed promise along these lines. But those who thought the approach had vanished may have been surprised to learn this week that the judge in the horrifying Aurora, Colorado, movie-theater massacre ruled that it could be used should the defendant in the case, James Holmes, opt to try the insanity defense. Most recently the judge himself registered a “not guilty” plea for Holmes because the defendant and his lawyers were not ready to formally enter a plea. A “not guilty” plea would circumvent the possible use of truth serum, but the debate on the ethics and efficacy of the approach already has been launched.

The facts in the case are well-known, yet remain hair-raising. Holmes is accused of dressing in combat gear, entering a theater on July 20 during the showing of The Dark Knight Rises, and then, after tossing smoke bombs into the auditorium, shooting at the crowd. He is charged with killing 12 people and wounding 58 others.

Truth serum, used for “narcoanalysis” or “narcosynthesis,” was first put forward 80 years ago by the psychiatrist William Bleckwenn, who found that some schizophrenics with catatonia and mutism could be softened into speaking lucidly if given drugs such as the short-acting barbiturates Sodium Pentothal and sodium amobarbital (Amytal). In addition, Bleckwenn used hypnosis to try to achieve a similar state. The goal was to lower the patient’s natural defenses enough for him to spill the beans on whatever he otherwise was withholding. In the psychiatry-mad 1950s, the drugs were used in legal cases as if they could unlock the truth; optimistic reports proliferated, many of them rather lurid and most tracing the approach to the Romans’ declaration of in vino veritas. Forensic psychiatrists felt they had found the mother lode, the path straight into a patient’s heart of darkness.

Oh, well. Enthusiasm dimmed for several reasons. First came the realization that results obtained under such conditions were not always reproducible. In addition, a philosophic quandary arose as people became less convinced that a single immutable truth ever could be arrived at. After all, as another ancient Roman, Marcus Aurelius, wrote almost 2,000 years ago, “everything we see is perspective, not the truth.” In Philosophy 101 terms, this means two people witnessing the same event might recall the sequence very differently, even if both were telling “the truth.” What, then, was the truth that the truth serum was seeking to impel?

Forensic psychiatrists felt they had found the mother lode, the path straight into a patient’s heart of darkness.

In the end, the ethical implications of using a drug to pull statements from otherwise unwilling people began to gnaw. The question remains hotly debated—some consider the approach coercive if not abusive, while others see only a practical solution to one of the oldest problems in society: dishonesty.

For Holmes, the idea is to use the approach only to see whether his insanity defense, should he go down that path, is well founded and not duplicitous. Perhaps, the judge believes, under the sway of drugs, the defendant may admit to a more premeditated and deliberately ruthless action than that implicit in an insanity defense. The magic drug might—might—melt away an elaborate con game and reveal the conniving evil man within. Maybe.

The discussion of the role of truth serum in the American judicial system is a worthy one. However, this particular nightmarish case seems the wrong place to start. Yes, the drug may unmask an otherwise concealed truth and move the Holmes case in one direction or another. It surely will create a buzz, as one side calls experts about the wonders of the approach and the other calls equally credible people who will swear the approach is unreliable. The press, too, will find even more experts as reporters excitedly move through previously undiscovered waters.

But this flurry of excitement would serve only to steer the trial away from the real issue at hand: gun control. According to reports, a 25-year-old seeing a psychiatrist after a profound change in personality legally acquired two Glock 22 pistols, a Remington Model 870 shotgun, and a Smith & Wesson M&P 15 semiautomatic rifle. Months before, he had gone online to buy thousands of rounds of ammunition for these weapons. Without provocation, he allegedly used the weapons to murder 12 people in cold blood. Endless discussions of the role of “truth serum” will serve only to allow gun proponents to walk away untouched from yet another national tragedy and therefore avoid confronting the real truth about the malevolent role of firearms in daily American life.