The New York Times has reported that, according to three sources, special counsel Robert Mueller is trying to stitch together an obstruction of justice case against President Trump based on his public tweets, TV appearances, conversations with public officials and other entirely lawful acts. If this is true, it suggests that there is no “smoking gun” or fire, not even any kindling. It suggests that all Mueller seems to have is some dry twigs from which he is trying to build a bonfire. The New York Times headline, “Mueller Looking for Obstruction in Trump Tweets,” should raise a red flag for all civil libertarians. This is exactly the kind of creative manufacturing of crimes from innocent and indeed constitutionally protected acts that endangers the liberties of all Americans.

Just imagine a prosecutor going through all of your tweets, all of your conversations, and all of your emails in search of a plausible theory of criminality based on a statute such as obstruction of justice. If Mueller manages to cobble together an obstruction of justice case from innocent communications, then this dangerous precedent will lie around like a loaded gun ready to be used by any vindictive prosecutors against any plausible target. That could be you or someone you love. It could be a Democrat or a Republican. It could be a liberal or a conservative.

{mosads}In the brilliant and increasingly relevant book, “Three Felonies a Day,” the experienced attorney and author Harvey Silverglate describes a “game” prosecutors play. One of them names a known target, and the others scour the criminal code to find three felonies he or she may have committed. If the report is accurate, Mueller and his team may be playing this game with a real live target, namely, President Trump.

I recall a case when the Equal Rights Amendment was pending and the votes of Illinois legislators were essential to secure ratification by that state. A naive young woman approached a legislator and offered a contribution to his campaign in exchange for a commitment that he would do the right thing and vote for equal rights for women. The woman was arrested and charged with attempted bribery under a vague statute.

Civil libertarians were properly outraged in that case. Defenders of Mueller will surely argue that it is common for prosecutors to stitch together innocent conduct to manufacture a crime, especially when the target is a suspected drug dealer, a terrorist or gangster. Tragically, they are right. There are such cases, but there should not be. Many wrongs do not make a right. Moreover, in those cases, the underlying conduct is generally done in secret. Here, Mueller evidently is trying to turn public communications, core First Amendment expressions, into a crime.

The time has come, indeed it is long overdue, for all Americans to take a hard look at broad and ambiguous statutes, which empower prosecutors to be “creative.” There is a concept in criminal law known as lenity. If there are numerous ways of interpreting a statute, the law requires that it be interpreted in the most reasonably narrow way, so as to avoid empowering prosecutors to target unpopular defendants. Failing to apply this concept to constitutionally protected emails, tweets, messages, and other forms of communication should concern every civil libertarian, even those who are anxious to find legal weapons with which to target President Trump.

Imagine if Hillary Clinton had been elected and a special counsel was trying to stitch together an obstruction case against her for allegedly erasing emails, using her own home server, and taking other ambiguous actions. Democrats would immediately become civil libertarians and denounce such a “witch hunt.” Now it is the Republicans who are calling the investigation a “witch hunt.” That term may overstate what is happening, but the danger of criminalizing political differences is real.

The problem with turning communications, which by themselves are not criminal, into a criminal obstruction case is that life is lived prospectively while prosecutors look at evidence retrospectively. As the philosopher Soren Kierkegaard put it, “Life can only be understood backwards, but it must be lived forward.” In legal terms, this means that isolated statements may have an innocent intention at the time they were made, but when looked at backwards, they may appear to be part of a guilty pattern. Even more fundamentally, crime requires both guilty acts and guilty intentions.

There is considerable danger in turning innocent acts, especially constitutionally protected ones, into criminal obstruction based on an intent inferred after the fact from a pattern that may not have been contemplated at the time. This is what Mueller seems to be doing, if the report is accurate. All of us who care about preserving civil liberties and the rule of law should be concerned about this dangerous approach to stitching together a guilty fabric from innocent threads.

Alan M. Dershowitz is the Felix Frankfurter Professor of Law, Emeritus, at Harvard Law School. He is the author of “Trumped Up: How Criminalizing Politics is Dangerous to Democracy” and “The Case Against Impeaching Trump.” He is on Twitter @AlanDersh and Facebook @AlanMDershowitz.