Paxton submitted court filings that the Obama administration had "conspired to turn workplaces and educational settings across the country into laboratories for a massive social experiment" and termed the directive a "gun to the head" that threatens the independence of school districts. The states dropped the suit after the directive was revoked by President Donald Trump. Paxton is involved in a legal challenge to a rule by the Department of Labor which forces employers to report any "actions, conduct or communications" undertaken to "affect an employee's decisions regarding his or her representation or collective bargaining rights." Known as the "Persuader Rule," the new regulation went into effect in April 2016. Opponents of the rule say it will prevent employers from speaking on labor issues or seeking legal counsel. In June 2016, a federal judge granted a preliminary injunction against the rule. Paxton called the injunction "a victory for the preservation of the sanctity of attorney-client confidentiality." In 2016, Paxton was one of 11 Republican state attorneys general who sided with ExxonMobil in the company's suit to block a climate change probe by the Commonwealth of Massachusetts. Paxton and the other state AGs filed an "amicus curiae" brief, contending that Massachusetts Attorney General Maura Healey used her office to "tip the scales on a public policy debate, undermine the first Amendment and abuse the office's subpoena power." Healey had launched a probe of ExxonMobil's historical marketing and sale of fossil fuel products, requiring the company to produce 40 years worth of documents regarding fossil fuel products and securities. Healey said the documents would prove that ExxonMobil "knew about the risks of climate change decades ago and fraudulently concealed that knowledge from the public." The amicus brief supported Exxon Mobil's motion for a preliminary injunction. Paxton questioned Healey's use of law-enforcement authority regarding the global warming controversy, which he called an "ongoing public policy debate of international importance." Paxton described Healey's attempts to obtain historical company records for a public policy debate as a threat to freedom of speech, stating: "The Constitution was written to protect citizens from government witch-hunts that are nothing more than an attempt to suppress speech on an issue of public importance, just because a government official happens to disagree with that particular viewpoint." The brief portrayed climate change as an issue that was still a matter of scientific debate, although in fact the scientific consensus is that the earth is warming and human activity is primarily responsible. U.S. Virgin Islands attorney general Claude Walker had also issued a subpoena for Exxon's records.