Constitutional legal cases are, at times, ponderous and dense with seemingly-arcane hairsplitting to determine what the Constitution really means in the modern word, or when viewed with modern attitudes. Sometimes, however, constitutional cases are pretty easy to understand, because virtually everyone can relate to the circumstances which brought it to court in the first place. An injunction just issued by a federal judge falls into the second category, because it affirms the right to free speech -- specifically, the free speech of an automobilist flashing his headlights at oncoming traffic to warn of an impending speed trap. Obviously, this is something most who have driven cars can relate to on a very personal level.

Headlights, when intermittently signaled to other drivers -- either by the "momentarily going to high beam" flash or the daylight "click them on and off" style flash -- are undoubtedly a means of communication, the judge ruled. As such, this means of communication is protected under the First Amendment's right to free speech. It sounds pretty simple, and on the face of it, it is. There are nuances, but the basic concept is easy.

From personal experience, flashing headlights communicate a rather limited range of messages out on the open roadways of America. On the long between-cities stretches of the Interstate highways, they have one benign use which not everyone knows, but which aids everyone's safety: telling a passing truck he is clear to return to your lane. If you're in the slow lane, and a semi goes by you in the fast lane, the truck usually wants to return to the slow lane after overtaking you. So you wait until his rear bumper is safely beyond your car, then you flash your headlights at him or her to let him or her know that safe clearance now exists to move back right. This is usually followed by the truck flashing the trailer's running lights as a way of saying "thank you." That one is my personal favorite.

Of course, flashing headlights can also be used to communicate an aggressive message. When traveling in the fast lane, at times you meet slowpokes (what a local newspaper traffic columnist where I live has amusingly labeled "road boulders") who don't want to keep up with the flow ("the flow" being "how fast I want to travel in the fast lane," of course). Flashing headlights, in this instance, means "Hey, buddy, ya wanna move it over?" Which is not as benign as the previous example, especially since some tailgating usually precedes this communication.

But normally a headlight flash is a safety warning of one sort or another. The most common of these is a warning to an oncoming car that their headlights aren't on (at night), or that they've left their highbeams on.

The court case, however, focused on the final message commonly communicated by flashing headlights. In the generic use, such a message is a warning: "Danger ahead! Slow down!" But in the specific, especially in regions where such things are common, its meaning is clear: "Speedtrap ahead! Slow down!" Apparently, in some jurisdictions, the authorities got so annoyed at such warnings that they attempted to make them illegal. This is what the judge just ruled is an unconstitutional infringement of free speech.

The injunction the judge issued is only eight pages long (PDF version is available) and is not a ruling on the actual merits of the case, but it is pretty clear which way the wind is blowing from how the judge described the legalities involved. The facts were undisputed by both sides: Michael J. Elli saw a speedtrap, then flashed his headlights at oncoming traffic. He was seen doing so by a police officer, who pulled Elli over and ticketed him. Written on the ticket was: "[f]lashing lights on certain vehicles prohibited. Warning of RADAR ahead." The law used to cite Elli states:

Limitations on Lamps Other than Headlamps -- Flashing Signals Prohibited Except on Specified Vehicles

Any lighted lamp or illuminating device upon a motor vehicle other than headlamps, spotlamps, front direction signals or auxiliary lamps which projects a beam of light of an intensity greater than three hundred (300) candlepower shall be so directed that no part of the beam will strike the level of the roadway on which the vehicle stands at a distance of more than seventy-five (75) feet from the vehicle. Alternately flashing warning signals may be used on school buses when used for school purposes and on motor vehicles when used to transport United States mail from post offices to boxes of addressees thereof and on emergency vehicles as defined in Section 300.010 of this Title and on buses owned or operated by churches, mosques, synagogues, temples or other houses of worship and on commercial passenger transport vehicles that are stopped to load or unload passengers, but are prohibited on other motor vehicles, motorcycles and motor-drawn vehicles except as a means for indicating a right or left turn.

The second part lays out who can use flashing lights on a vehicle. But it is obviously written to address the sort of flashing lights you see on emergency vehicles, school buses, and postal vehicles. It really doesn't address flashing headlights at all.

But there are several things to consider about the free speech claim. The biggest one, for the defendant, was that the judicial system even threatened to use "obstruction of justice" against him (the municipal judge, at his first court appearance, used this exact phrase in a warning to Elli). When it got to federal court, the city being sued "suggested that flashing headlamps might be illegal interference with a police investigation." In other words, warning drivers of a speedtrap is illegal because it interferes with the cop's ability to catch people speeding. But the judge noted that the Missouri statute states clearly:

[T]he crime of hindering prosecution if for the purpose of preventing the apprehension, prosecution, conviction or punishment of another for conduct constituting a crime he... [w]arns such person of impending discovery or apprehension, except this does not apply to a warning given in connection with an effort to bring another into compliance with the law[.]

Since that is exactly what flashing your lights is intended to do -- tell other drivers to slow down, bringing them in compliance with the speed limit law -- it does not apply here. It is not obstruction of justice to aid others in complying with the law. The judge even pointed out that the Missouri department which issues drivers' licenses "recommends drivers flash their headlamps to warn other drivers of emergencies," further undercutting the city's position. Elli was not pretending somehow to be an emergency vehicle by flashing his lights, and he was not urging others to get away with breaking the law. Quite the contrary -- he was urging others to obey the law, because if they didn't they would get caught in the speedtrap.

There's an element of "thoughtcrime" to the issue, as well. The cops pull people over who flash their lights -- even though flashing your lights is not illegal per se -- because they think they know exactly what message is being conveyed. They are asserting, in essence, that they can read the minds of the drivers who flash their lights. But this doesn't even really matter, because the message itself is completely legal, too.

Flashing headlights pretty clearly means "Slow down!" no matter what the danger on the road ahead may be (an accident, a patch of ice, a stray dog, or a speedtrap). But even "Slow down -- speedtrap ahead!" is protected speech under the First Amendment of the Constitution. Someone standing on the side of a road with a sign which read "Speedtrap Ahead" is merely exercising their freedom of speech. The judge agreed, and explicitly stated that "communicating a message that one should slow down because a speed trap is ahead and discovery or apprehension is impending, that conduct is not illegal." Put plainly, the cops have no right to make such speech illegal -- there is no right of secrecy for police in the Constitution.

At some point, the city realized their position was a tenuous one. Although Elli entered a plea of not guilty, the case never got to trial in municipal court, because the city decided to drop the charges (the municipal judge stated that the fine usually assessed was $1,000 -- not exactly pocket change). Elli persisted in federal court on civil rights grounds, and the city then told the judge they are no longer enforcing the law in this manner. The federal judge, though, wasn't buying this -- because it is obviously not a permanent solution (the city could change its mind at any time and start writing tickets once again). So he issued an injunction against the city. Hopefully, the case will end by declaring unequivocally that it is absolutely unconstitutional to even pass a law forbidding flashing your lights to warn of speedtraps. The freedom to flash will then be safe, at least in Missouri.

The Bill of Rights, as a whole, was created to limit governmental power. It is full of things the government is forbidden to do, in fact, from beginning to end. The men who composed it were not big fans of the police having overly-broad powers. Warning citizens that governmental police powers are being used is indeed part of the First Amendment's guarantee of freedom of speech.

After all, what would they have thought if the defendant in such a case was named "Paul Revere"?

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant