Pretextual stops

"Show me the man, and I'll show you the crime" was one of the mottos of the secret police of the Stalinist Soviet Union (notoriously coined by its secret police chief). This is in general used to describe the mentality and behavior of tyrants and oppressive authorities who will always find some kind of excuse for punishing someone using outwardly legal reasons. After all, law books are really vast, with literally thousands and thousands of laws, codes and ordinances, which are so extensive and numerous that it's almost impossible for the average citizen to never break any of them in the slightest. You have probably technically broken at least some laws or codes, no matter how small, during the past week alone, probably without even knowing.

In totalitarian regimes this principle has been and is often used for political persecution of dissenters and other undesirable people (while still maintaining a facade of legality). At a slightly smaller level, even in free democratic constitutional countries, this is way too often used by authorities, such as police officers, to find pretexts to investigate or even harass someone they don't like.

Indeed, for example in the United States (and several other countries) pretextual traffic stops are an extremely common practice, all throughout the country. "Officially" these are used for the police to have a legal excuse to stop one who they suspect of some crime, in order to give them an opportunity to investigate. In other words, the police will start following the suspect while he's driving, and if he commits any traffic violation, no matter how small and inconsequential (such as starting to move a second before a traffic light becomes green), they will stop him and use it as an excuse to investigate the actual crime they are investigating. Usually they aren't even interested in the traffic violation itself, and are just using it as an excuse to stop the person (and have eg. a valid reason to get his ID, etc.) Usually they can do this very easily because it's very hard to drive without ever making any sort of minor technical violation of any kind.

These pretextual stops, at least in the United States, are not technically illegal, but they are ethically questionable, and court decisions on their validity tends to vary quite a lot from case to case.

Of course that's the most legit form of pretextual traffic stops. There are much more corrupt forms of it. The technique is quite widely used to simply harass someone that the police don't like: Just keep following the person for long enough, and at some point he will commit some traffic violation, no matter how small, and that will give them an excuse to harass the person. And believe me, cops know how to really harass someone "legally" if they want to. They can "suspect of him driving under the influence" and humiliate him by having him go through a barrage of sobriety tests, they can have canine units come for a sniff (obviously no need for the canine unit to hurry to the scene, he can take his sweet time), and so on and so forth. They have an entire arsenal of "legal" ways to harass a driver during a traffic stop.

This is not restricted to the United States either. It happens all over the world. Even in Finland, which has one of the least corrupt police forces in the world, there are proven cases of police harassing or trying to harass people they don't like, in this exact manner. (In one particular documented example police officers followed a journalist who had made many stories criticizing corruption among the police forces, and they followed him literally for several hours, trying to catch him for any traffic violation. This was all caught on police radio, which the journalist himself was listening to, and thus knew to drive carefully. There are also documented cases of them following celebrities in order to fine them hefty sums, for some reason.)