Thanks for your reply, Rhythymdvl. I can appreciate you think we’d be more solid ground arguing under the 5th Amendment.
If you don’t mind, let me throw one more case at you to see if it changes anything:
It’s a 1986 case. Colorado v Connelly. With a hat tip to section II of Rehnquist’s opinion. Hopefully I didn’t botch the link on my phone.
As a counterpoint, consider the Napoleonic code, the concept under which a lot of the world outside the old British Empire operates.
As I understand it, the defendant is obliged to take the stand, and must answer the questions put to him. The only special consideration is that a defendant cannot be prosecuted for perjury for what they say on the stand; the concept is that a guilty man will say anything to get off, and you cannot put the person in the position of “damned if you do, damned if you don’t”. The trial is more like an inquiry than a debate - the judge asks questions too.
In the OP’s premise, as with the protection of the 4th and 5th, the goal is to prevent the overwhelming power of the state against an individual from being used on fishing expeditions. Lazy cops will simply haul in and interrogate everyone with their “truth serum” until they find the guilty party, much as the authorities used torture to get at the “truth” they wanted (and produce confessions for public show) in the middle ages.
In fact, there was an Isaac Asimov SF mystery story from the 1950’s dealing with this specific subject. (Nothing is new) The authorities wanted to know if a particular person was guilty of murder. The twist was, the law said a person could only be subject to mandatory truth serum interrogation only once in his life - Asimov’s protection clause against government abuse. The police were worried that a lot of criminals would fake the circumstances to look guilty so they would then have a lifetime immunity from drugged interrogation. The result was like the old lawyer saying “don’t ask questions unless you already know the answer.”
I note your hypo posits a “truth serum.” There ain’t no such animal – if your hypo was intended to actually imagine there is some scientifically verifiable drug that forces the truth out of a person, my argument changes, because the existence of such a drug would be a matter of first impression for the legal system – I assume you merely mean the kind of suggestible state induced by sodium pentothal or scopolamine.
That said… I’d argue the Fifth Amendment.
It’s been a long-standing principle of common law that involuntary confessions are inherently untrustworthy. See, e.g., King v. Warickshall, 1 Leach 262, 263-264, (K. B. 1783) (“A free and voluntary confession is deserving of the highest credit, because it is presumed to flow from the strongest sense of guilt … but a confession forced from the mind by the flattery of hope, or by the torture of fear, comes in so questionable a shape … that no credit ought to be given to it; and therefore it is rejected.”)
The case I mention above, *Bram v. US, 168 U. S. 532 (1897), clearly lays out the Fifth Amendment claim (and clearly pre-dates Miranda) (the requirement of a voluntary confession "is controlled by that portion of the Fifth Amendment … commanding that no person `shall be compelled in any criminal case to be a witness against himself ’ ")
If we were having this conversation in 1950, you’d have a point: the first half of the last century primarily used the Due Process clause – Ashcraft v. Tennessee (1944); Chambers v. Florida (1940); Malinski v. New York (1943).
But since Malloy v. Hogan (1964), the Court has applied the Fifth Amendment, and hooked it into the states via the Fourteenth, rather than continue to evolve the Due Process protections directly against the coerced confession. That’s simply the way the caselaw has developed.
Gee, I wish I had thought to mention Malloy.
The problem with Brown v. Mississippi is that coercion by physical violence is a Due Process Clause violation regardless of whether the resulting confession is later admitted; due process is required to administer the beating itself.
That’s why it makes much more sense to leave out the pure due process issue and focus on the Fifth (and its incorporation against the state through the Due Process Clause.)
Oh, and Poul Anderson had a story - how do you lie to a telepath? Hint, by believing it yourself thanks to a “gullibility serum”.
Which brings up the problem that a lot of people with assorted problems live in altered states where they may believe things that are not true. Often, these are the sort of people brought to the attention of authorities. What does the state do when their “guaranteed true” interrogation contains obvious falsities? Is every inconsistency explained away as “defendant is confused on this point”?