New York Attorney General Eric Schneiderman is pursuing an investigation of the Exxon Corporation in part for making donations to think tanks and associations like the American Enterprise Institute and American Legislative Exchange Council, which mostly work on issues unrelated to the environment but have also published some views flayed by opponents as “climate change denial.” Assuming the First Amendment protects a right to engage in scholarship, advocacy, and other forms of supposed denial, it is by no means clear that information about such donations would yield a viable prosecution. Which means, notes Hans Bader of the Competitive Enterprise Institute, that the New York probe raises an issue of constitutional dimensions not just at some point down the road, but right now:

A prolonged investigation in response to someone’s speech can violate the First Amendment even when it never leads to a fine. For example, a federal appeals court ruled in White v. Lee, 227 F.3d 1214 (9th Cir. 2000) that lengthy, speech-chilling civil rights investigations by government officials can violate the First Amendment even when they are eventually dropped without imposing any fine or disciplinary action. It found this principle was so plain and obvious that it denied individual civil rights officials qualified immunity for investigating citizens for speaking out against a housing project for people protected by the Fair Housing Act.

In another case, in which a company had been sued seeking damages over its participation in trade-association-related speech, a federal appeals court found that the pendency of the lawsuit all by itself caused enough of a burden on the firm’s speech rights that the court used its mandamus power to order the trial judge to dismiss the claims, a remarkable step.

Moreover, Bader writes, a string of federal precedents indicate that the constitutional rights Schneiderman is trampling here are not just Exxon’s but those of the organizations it gave to, which have a right to challenge his action whether or not the oil company chooses to do so:

These groups themselves can sue Schneiderman under the First Amendment, if Schneiderman’s pressure causes them to lose donations they would otherwise receive. Government officials cannot pressure a private party to take adverse action against a speaker.

Meanwhile, writing at Liberty and Law, Prof. Philip Hamburger of Columbia Law School takes a different tack: the subpoenas imperil due process and separation of powers because they issue at the whim of Schneiderman’s office. Earlier ideas of constitutional government “traditionally left government no power to demand testimony, papers, or other information, except under the authority of a judge or a legislative committee.” In more recent years executive subpoena power has proliferated; so has the parallel power of lawyers in private litigation to demand discovery, but the latter at least in theory goes on under judicial supervision that can check some of its abuse and invasiveness. Extrajudicial subpoenas by AG offices are particularly dangerous, Hamburger argues, because of their crossover civil/criminal potential: the targets do not enjoy a high level of procedural protection when “attorneys general claim to be acting merely in a civil rather than a criminal capacity,” yet the same offices can and do threaten criminal charges. Especially dangerous is New York’s Martin Act, a charter for general invasion of the private papers of anyone and anything with a connection to New York financial transactions.

An attorney general’s concern about fraud or the “public interest” is no justification for allowing him to rifle through private papers. When he thereby extracts the basis for a criminal prosecution, he evades the grand jury process. When he thereby lays the groundwork for a civil enforcement proceeding, he evades the due process of law, for there ordinarily is no discovery for a plaintiff until he commences a civil action. Even worse, when a prosecutor uses a subpoena to get a remunerative settlement, it is akin to extortion — this being the most complete end run around the courts.

Previously on the probe here and here (and earlier here and here), and on the New York attorney general’s office here and here.