Jeff Jacoby’s vitriolic column (“Healey’s Exxon witchhunt,’’ Opinion, Dec. 11) goes way overboard in accusing Massachusetts Attorney General Maura Healey of running “roughshod over the First Amendment in pursuit of a political agenda.’’ He appears to believe that the attorney general’s office has no legal authority to issue a civil investigative demand, or CID, in its attempt to establish whether ExxonMobil has “misled the public, including its investors and consumers, with respect to the impacts of climate change.’’

In fact, the attorney general’s office has issued some 200 CIDs (under Chapter 93 A) since 2013 in pursuing suspicions of “unfair and deceptive practices in the conduct of business.’’ Some notable joint s with other states include, most recently, investigation of Volkswagen’s “clean diesel’’ deception and now, with New York’s attorney general, the ExxonMobil investigation. This is not Healey’s “own crusade to punish freedom of speech,’’ as Jacoby asserts.

A more likely cause for her forthrightness is enforcement of the Commonwealth’s Global Warming Solutions Act of 2008, which stipulates that the state’s greenhouse gas emissions be reduced by 25 percent by 2020 and 80 percent by 2050. This is exactly the mandate that the Executive Office of Energy and Environmental Affairs is working to put in place.

We should be grateful for the attorney general’s actions, which will moderate the disproportionate voice of big oil in the Commonwealth and make the realization of the state’s climate goals more attainable.

Bill Green

Cambridge