This commentary originally appeared in The Daily Caller on July 31, 2015.

Few Americans would expect posting online about car engines, fertilizer, or general engineering principles to land them in prison. But if the aspiring censors at the State Department get their way, such innocent discussion would be prohibited as “exports” of military technology.

The Obama administration announced last month that it intends to require anyone discussing broad categories of “technical data” to ask for government permission before posting the information online. Ostensibly it is an effort to keep weapons out of the hands of foreign militaries under the International Traffic in Arms Regulations (ITAR). But “technical data” is defined so broadly as to outlaw much of the Internet.

The rule defines “technical data” as anything that would be “required” to “manufacture” or “develop” items on a long list of weapons including almost all firearms as well as tanks, bombs, and battleships. The problem caused by the over breadth of this definition is the tremendous amount of non-military information required to develop or manufacture military technology.

Imagine for a moment the non-military knowledge required to produce even a simple weapon, like a hunting rifle. One must know the diameter of the barrel, how to make a spring for the trigger, and of course basic physics. The knowledge required to make a battleship or tank quickly encompasses a great deal of civilian technology: how to make an engine more efficient, how to make steel stronger, or even the best design for a boat’s propeller. “Bomb” is also on the munitions list, so discussing fertilizer advancements would be prohibited since the resulting fertilizer could be used to make a bomb.

Unfortunately, ITAR’s overbreadth is not the result of sloppy drafting. Realizing the broad scope of its definition of “technical data,” the government saw fit to exclude basic “scientific, mathematical or engineering principles” so long as they are “commonly taught” in academic institutions. That’s right: many basic engineering principles not commonly taught in academic institutions will be illegal to discuss online without government permission.

The proposed rule also removes the exclusion for basic advertising information, giving the State Department power to prosecute those who provide too many details about their products. That will not help American competitiveness or consumers, and it is likely to be used to target companies unpopular with the administration.

Granted, an exception exists for information already in the “public domain.” But, in an Orwellian twist, the new rule redefines “public domain” to include only information approved for publication by a federal agency. So, the public domain exclusion does nothing to allow individuals to speak without government permission — even if they are saying something that can already be found on the Internet.

Because the administration’s chosen censorship tool is a statute aimed at international spies, the penalties are quite severe. One ITAR violation may result in up to 20 years incarceration and a $1 million fine. So before you discuss anything technical online, you better either make sure it’s “commonly taught” at an academic institution or get a permit from the State Department.

The Administration’s proposal constitutes a clear violation of the First Amendment — not to mention the Second. And the government cannot rely on some sort of national security exception to free speech. In the 1971 case of New York Times v. United States, the Supreme Court rejected the government’s authority to stop the publication of the Pentagon Papers—classified information pertaining to American military activities in the then-ongoing Vietnam War. In the face of that decision, the Obama Administration cannot claim to have the authority to license the discussion of basic firearms, engineering principles, or car engines online — even if it would help prevent the Islamic State from obtaining the latest in American deer rifle technology.

The regulatory regime embodied in the proposed rule will not and cannot ban all of the speech it encompasses. Instead, it will be a weight hanging over the Internet, ready to drop whenever the government finds speech it wishes to suppress, chilling the expression of ideas and development of new technology in the mean time. Our Constitution does not tolerate such a regime, and nor should our government suggest one.

Joel Stonedale is an attorney at the Texas Public Policy Foundation’s Center for the American Future.