Mississippi Attorney General Jim Hood launched a broad investigation of Google search results in October. On Friday, after reports on Ars and elsewhere showed the investigation involved heavy MPAA involvement, Hood backed off, saying he wants to "call a time out so that cooler heads may prevail."

That hasn't put an end to the chief concern: the entertainment industry may try to get by other means what it couldn't get from Congress, when the SOPA and PIPA anti-piracy bills went down in flames.

Trade groups that represent the industry's biggest companies along with several public interest groups sent a letter to Hood this afternoon reminding him about how widely unpopular SOPA was. Attached are several other letters from prominent persons and groups who fought against SOPA back in 2011. The letter (PDF) doesn't mention Google by name. It reads in part:

According to recent news reports, your office, in active coordination with the Motion Picture Association of America (MPAA) and its member companies, has been and remains engaged in a coordinated campaign to shut down and block access to individual websites through backdoor methods resoundingly rejected by the public and federal lawmakers... It is our understanding that those efforts include developing legal theories and even drafting civil investigation demand letters for state attorneys general to facilitate actions against websites and search engines. The goal of these efforts mirrors the goal of SOPA: to create new legal tools that will compel online service providers to remove content from the Internet with little, if any, meaningful due process. When Congress tried to pass SOPA in 2011­-2012, millions of Americans signed petitions, called and e-mailed their Congressional representatives, and commented on social media platforms, all firmly opposing attempts to limit online speech by blocking websites without appropriate legal process. SOPA was a bad idea at the federal level, and any SOPA revival on a state level is an equally bad idea that, we are confident, will be equally unacceptable to the public. We have included several letters highlighting the original opposition to SOPA to remind you of the depth of the problems with this approach and the principled opposition to curtailing free speech that it first provoked. Sincerely, American Library Association

Center for Democracy and Technology

Computer and Communications Industry Association

Consumer Electronics Association

Demand Progress

Engine Advocacy

Electronic Frontier Foundation

Free Press

Freedom Works

New America’s Open Technology Institute

Public Knowledge

Rootstrikers

R Street

The attached letters are a blast from the not-very-distant past (Internet activism, circa 2011). They include a letter signed by dozens of prominent Internet engineers, including Vint Cerf, warning about how SOPA could fragment the global Domain Name System. 160 Web entrepreneurs joined in on the letter as well, noting that blacklists of sites "supporting piracy" ended up including Vibe Magazine and the Internet Archive.

The lobbyists who pushed for an investigation into Google were hoping that other states would follow Hood's lead. That hasn't happened yet.

In today's letter, tech groups are warning that anyone who messes with the structure of the Internet—including search—could cause a SOPA-level public uproar. Three years after the SOPA debate, the question is, are their opponents ready to take that risk?