Six months ago, New York Attorney General Eric Schneiderman issued a subpoena demanding that Exxon Mobil turn over records concerning its research on climate change. In March, Mr. Schneiderman took the predictable next step, announcing that a coalition of attorneys general will hold fossil fuel companies accountable. “The First Amendment, ladies and gentlemen, does not give you the right to commit fraud,” he said.  The threat to scientific inquiry and political speech is obvious. Not so widely recognized is the underlying violation of due process. Start with the fact that Mr. Schneiderman and the other attorneys general have relied, as their opening move, on a nonjudicial subpoena to force the disclosure of information.  Traditionally, federal and state governments could demand testimony, papers or other information in only very limited ways. A legislative committee could call witnesses and insist that they appear and testify. But an attorney general who wanted to rifle through a private company’s filing cabinet had to get a warrant signed by a judge based on probable cause, or had to ask a court overseeing a grand jury to issue a subpoena.  Otherwise the attorney general had to wait until he brought civil or criminal charges, and in a criminal case he could get only a very limited version of discovery. As the founding generation knew from experience, government demands for papers could be dangerous.  Much has changed over the past century. When civil discovery of evidence, now a common process, evolved in the late 19th and early 20th centuries, some states, for the sake of convenience, allowed subpoenas for such purposes to be signed not by judges, but by clerks, and then even by parties in cases. The subpoena power thus began to drift out of the hands of the judiciary.  Although this initial step was trivial, it offered legitimacy for what followed: Over the 20th century, Congress gave administrative agencies, from the Agriculture Department to the Department of Health and Human Services, statutory authority to issue subpoenas in their own name. And state legislators have granted such power to their equivalent agencies.  All sorts of administrators, at both levels of government, thereby acquired an expansive power to demand information without initially working through a judge. This was bad enough, but it gets worse. Lawmakers also granted subpoena authority to their attorneys general. New York did so in 1921. Even prosecutors thus can now read through private papers on demand.  The Supreme Court upheld the subpoena power of agencies in United States v. Morton Salt (1950), on the theory that administrators are exercising the power of a grand jury. This is improbable, but it is even more improbable for prosecutors, who lead grand jury proceedings. Having a role in facilitating grand juries, a prosecutor cannot, by himself, be assumed to act as one. Even if the Morton Salt argument really justifies administrative subpoenas, it cannot explain an attorney general’s subpoena.  Nor can the dangers of giving a subpoena power to prosecutors be waved away. In a grand jury, a judge oversees the proceedings to prevent excessive intrusions into private papers and lives. In a government agency, the administrator typically is not an elected official, and therefore is not using the subpoena power to generate public support for his own political campaign. But when an attorney general issues a subpoena, the opposite conditions prevail: There is no ongoing judicial supervision and far too much politics.  Regrettably, this evasion of judicial subpoenas is only the beginning of the due-process problem, for Mr. Schneiderman and other attorneys general have the power to bring not simply administrative, but criminal, charges on the basis of the information they force out of private parties. They thereby dangerously combine the roles of grand jury and prosecutor.  If Mr. Schneiderman were bringing a civil case, he could seek discovery only after filing a complaint about a concrete injury, and his demands would be subject to judicial supervision, including protective orders to narrow their scope. If he were bringing a criminal case, he would have difficulty getting much information at all from the defendant through discovery.  But with the usurped subpoena power, he can engage in a roving investigation, unlimited by any formal accusation, and then can use the results to bring criminal charges. This is a dangerous amalgam of grand-jury and prosecutorial power in one person. Mr. Schneiderman’s subpoena to Exxon Mobil thus stands apart. His ability to demand information in this way is a quintessential case of the fox guarding the henhouse.  The threats to privacy in our society are not merely technological; they also are legal. In addition to electronic surveillance, nonjudicial subpoenas allow government to examine private documents as if they were an open book. And as shown by Mr. Schneiderman, when attorneys general can issue such subpoenas, a valuable judicial power becomes a prosecutorial threat to liberty and due process.  Mr. Hamburger is a law professor at Columbia University and the author of “Is Administrative Law Unlawful?” (University of Chicago Press, 2014).
Philip Hamburger writes that in their zeal to pursue a climate-change agenda, attorneys general including New York’s Eric Schneiderman demanded Exxon’s files without first asking a judge. Whatever happened to due process?