Do We Eat Apples from a Poisonous Tree?

2017. január 22. 21:56 - Gord.ius

The Exclusion of Illegally Obtained Evidence and Comparative Constitutional Law - Part I.


How were the seeds of the “poisonous tree” planted in the practice of the Supreme Court of the United States? How did this tree yield a fruit that is just as poisonous? Poisonous, that is to the justice system. In other words: How was the exclusionary rule created, and why is it important for us today, surrounded by technology, dependent on electronic communication, which all provide fertile ground for growing “deprivacy practices”, i.e. serious violations of our most intimate secrets.



Since the dawn of time and Nardone v. United States, the practice of the Supreme Court of the United States (SCOTUS) has been creating exclusionary rules in terms of evidence obtained in breach of the constitution, which in Nardone they dubbed “the fruit of the poisonous tree”.

After Mapp v. Ohio, also decided by SCOTUS in 1961, similar was the case in terms of evidence obtained in violation of individual privacy under the umbrella of protecting the people against state abuse of power in conducting unreasonable searches and seizures prohibited by the Fourth Amendment to the Constitution of the United States.

Exclusionary rules have gradually started to show their face in US criminal procedure laws, then making their way into European criminal procedure and constitutional thought as well. In certain European countries, even civil procedure contains regulations against such “tainted” evidence.

 In Hungary, the Parliament has adopted a new text for the Civil Procedure Code in late 2016, which will enter into force in January 2018. According to the regulatory conception [1] submitted by the Government „unlawfulness on the one hand  might attach to the creation or production (e.g. through a transcript for unlawful wiretaps) of a document, or to the obtention or acquisition of an otherwise legally created document (e.g. stealing a document or violating confidentiality rules). In civil litigation, unlawful acts become significant if the party admits the incriminated document into evidence. The use of unlawfully created or obtained documents shall not be allowed in a civil suit (i.e. they shall not be evaluated as evidence) […]” [2] The new Code is the first ever to regulate the admissibility of evidence obtained through the violation of the (fundamental) rights of others in Hungarian civil procedure.

The regulatory conception of the new code itself suggests that in order to answer the outstanding questions of law in the above regards, „improvements to the current code or the introduction of a new direction of regulation might be useful (which neccessitates further, deeper comparative investigation).” [3] Driven precisely by this objective, in the following, we endeavor to shed light on some of the most pressing issues in this field, through a comparative analysis, with due regard to the fact that with the evolution of technology and the creation of many simple ways to violate individual privacy, the issue is far from becoming more simple.

Just think about family law litigation. In civil cases, such as in family law litigation, private parties, often without the interference of a third party (and never assisted by a state entity) can get their hands on the most sacred private secrets of their once loved ones, which they then can be free to use under the prevailing rules of civil procedure. This is currently the case in Hungary as well.

The present short article (as first of a three) will go at the issue from a broader point of view, looking at the big picture. We shall first analyze the multitude of procedural implications regarding the use of any evidence obtained unconstitutionally (i.e. through violation of the rights of others) as part of

  • the general „constitutional and procedural law climate” surrounding the issue of exclusion of evidence,
  • the foreign constitutional and procedural law patterns that exist (from a comparative constitutional law approach), which might serve as means for legal importing

What prohibits the use of such evidence at trial?

How to best preclude private information obtained in violation of the fundamental right to privacy to be used as evidence?

Procedural rules prohibiting the use of “tainted evidence” can be applied to the “digital scenarios” of the information society in a much more difficult manner. This is especially true in the case of a “slow jurisprudence” or “slow practice”, slow in the sense that it is unable to adequately follow the evolution of technology and adapt to the new challenges posed by the many “deprivacy” practices we may experience in our daily lives. (Please note, due to the narrower thematic bounds, most of our examples will have to do with family law and the delicate, internal privacy dimensions of the family entity.)

At first, just think of a husband who secretly plans on buying a diamond ring for her wife for their anniversary, but asks the opinion of some of the friends and family members of her wife for advice. Suppose he asks this advice in many private e-mails written to the above circle. These e-mails then belong to the inviolable sphere of privacy surrounding the husband and not even the wife has a right to violate this privacy despite the bond and relationship of confidence they exist in. The husband is entitled to have his privacy based on which he then can make his own decisions.

On a more procedural account, let us suppose that the ring the husband bought did not bring about the expected result and the marriage failed. In this case, all of the electronic mail (and all information contained therein, most of it considered private by every possible privacy-standard) written by both parties might become the subject of debate in a dissolution of marriage case.

Each other’s electronic correspondence is usually the domain where the parties first start to look for suspicious documents, right after looking through each other’s cellphones. In these cases, the parties use evidence obtained in breach of the other’s confidence and privacy as evidence supporting their own claims. The same is true for the compilation of evidence in a child custody case.

Bear in mind that these issues are not unprecedented, however, and not even a Hungarian invention. Not even at the intersections of technology and law, there is nothing new under the sun. As early as from the 1990s up until August 2010 British authorities have followed an established practice in family law cases dubbed Hildebrand rules, [4] based on which in any dissolution of marriage case evidence in the form of secretly taken or made copies of the other’s private statements, personal documents (also those detailing their own assets) and their own private correspondence could have been used and was declared admissible as a default setting. All this was based on a rationale that the parties have a duty of disclosure (to lay out all the facts of the case), which shall be full and frank.


With the lapse of time, a little less than 20 years later, however, following the covert copying of mass amounts of electronic data and documents, the UK Court of Appeal decided in Imerman [5] - a case based on facts signficantly similar to Hildebrand – that the spouses have a so-called duty of confidence toward one another, which means that as a family they are not one entity and both parties have a right to keep private records and to refrain from any form of breach of (spousal) confidence. (Besides, for these violations, the trial court has not even excluded the possibility of a tort action or of filing criminal charges.) [6]

It is evident then, that to answer the many questions that arise in terms of how to protect privacy in a fair trial, we need to first look at the neighbor’s garden and check whether their grass is greener. In other words, through the application of comparative and comparative constitutional law, especially through the use of transplants and other forms of legal importing, we might learn something from other legal systems being exposed to the same problems that we are facing these days.

Below and in the subsequent Parts, we endeavor to uncover some of the foreign constitutional and procedural, even jurisprudential solutions that other countries have applied in order to protect individual privacy in a fair trial.


Gábor Halmai [7] argues that “constitutional cross-fertilization”, i.e. legal importing, has three basic types:

  • transplantation (of legal rules between legal systems);
  • borrowing (certain legal institutions or rationales, reasonings); and
  • migration (of constitutional ideas, to be of manifold use in the legal system and practice of the recipient or host country, which gradually becomes bi-directional.)

When talking about constitutional transplants, we cannot but mention the theories of Roghina and Spector, [8] and argue that based on their findings, combined with those of Halmai, a new working definition comes together for constitutional transplants. In this approach, constitutional transplants can also be considered “processes of migraton”, through which

  • foreign constitutional institutions, norms, notions or ideas (more specifically a given constitutional text or doctrine) are transplanted into national law, and
  • certain constitutional ideas spread and exert international effect, resulting in the convergence of constitutional solutions to common problems. (We shall soon come back to the convergence argument.) Thus, also such institutions, norms, notions or ideas (and even progressive approaches connected thereto or independently thereof) can be considered constitutional transplants as well, which have been created or established as a result of these processes. [9]


Nelson Tebbe and Robert Tsai argue that constitutional borrowing is the practice of “importing doctrines, rationales, tropes, or other legal elements from one area of constitutional law into another for persuasive ends.” [10] Nonetheless, they add that we can talk about similar processes in all areas of law and that we should use these expressions – i.e. cross-fertilization, migration, borrowing, etc. – as synonymous to each other. We gladly oblige by calling all of these formulations transplants from here on out.  

So far the legal value of transplants has been mainly praised in private law, but it also shall be given some merit in comparative constitutional law, if we consider the constitutional convergence theory of Rosalind Dixon and Eric Posner. [11] In this, they posit that not only constitutional ideas but also constitutional systems and cultures converge, by giving similar or the same answers to similar or identical common problems. This convergence then – undoubtedly – provides fertile ground for transplantation from different legal systems, also in the field of exclusionary rules. Sometimes the seeds for such transplants might (only) be found in criminal procedure, but – through analogy – a (trans)plant can be expected in civil procedure as well, with some obvious modifications and necessary adjustments in the process.

According to Blum, transplants can be looked at from three points of view. We only mention this here because he calls attention to the dangers of adopting foreign law in the interpretation of criminal exclusionary rules in Israel. Blum’s [12] three approaches are the following:

  • Problem solving – its essence is that in order to solve common problems in converging legal systems, experience of comparative law is used through the provision of data to support certain policy options.
  • External imposition – its essence is that greater powers (mostly the United States) have a larger role in inducing systemic change through the application of a system of incentives and sanctions in the political and economic sphere).
  • Emulation – its essence is that certain operational principles are applied under different circumstances and in this regard the recipient or host countries rely on patterns of countries that they consider to be exemplary, that they emulate.

We think that transplants can indeed serve as means to improve a legal system and/or a constitution, be it through any direct effect they might have on the constitutional legislator (e.g. through external imposition) or indirectly on those who apply and interpret the constitution (e.g. through problem solving or emulation).

However, we shall exercise due caution, in light of the above, when relying on them.

Adopted doctrines must be adapted to suit local conditions, while accounting for factors that might influence their operation. And even if we choose not to adopt the laws of others, simply examining them may lead to a better understanding of ourselves.” – Blum argues, [13] and we agree.

Bearing in mind the supreme objectives of self-reflection and self-development, in the following, we intend to uncover a few possible transplants, patterns or samples through which the value of privacy in the 21st century could be best protected in litigation with very high privacy stakes, involving the use of unconstitutionally/unlawfully acquired electronic mail as evidence.

In a narrower context, the very illustrative American example of the fruit of the poisonous tree doctrine, established and applied in the criminal procedural jurisprudence of SCOTUS as said, has inspired our comparative investigation, whereby we intend to uncover traces of the rationale behind it in continental constitutional and procedural thought.

In conclusion of our preliminary thoughts we agree with the opinion of Stephen C. Thaman, who – in the context of criminal procedure – argued that the discretionary duty of the judge is not simple in those cases where fundamental rights are sacrificed on the altar of fair trial, and it is not an easy task to reconcile the severity of the violation of the right in question with the legal interest protected by that fundamental right. He also argued that it is not easy to decide what qualifies as a fundamental rights violation. [14] Therefore, in agreement with him, we propose alternatives to the judicial determination of these facts and argue that constitutional paths can and should also be considered to adequately regulate exclusion of evidence obtained and used in violation of one’s privacy rights.

Thaman aptly makes an important remark [15] regarding the above issues in civil law legal systems, and argues that where the trial judge is simultaneously the finder of fact as well, they should be given discretionary powers to decide on the above issues. In the papers that follow, we shall see whether he was right, but for now, we rest our case.


Dr. Sulyok Márton

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Links to the pictures: here, here, here and here.


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