If there is probable cause due to the activities of a drug trafficker, can a policeman place a GPS on the suspect's car without a search warrant?...

I would argue that the police officer acted illegally when he placed the GPS unit on the suspect’s car.  Therefore, any evidence collected by the GPS, or through investigations that were launched because of information from the GPS, should be excluded from evidence in a trial.

To prove this, we need to look first at United States v. Jones, which was a case that the Supreme Court decided in 2012.  In that case, law...

I would argue that the police officer acted illegally when he placed the GPS unit on the suspect’s car.  Therefore, any evidence collected by the GPS, or through investigations that were launched because of information from the GPS, should be excluded from evidence in a trial.

To prove this, we need to look first at United States v. Jones, which was a case that the Supreme Court decided in 2012.  In that case, law enforcement officers placed a GPS on a suspect’s car without a warrant.  The Supreme Court ruled unanimously that this was a violation of the 4th Amendment.  Clearly, then, warrantless GPS surveillance is generally illegal.

However, we know that courts do sometimes allow warrantless searches of people, cars, or even homes.  Most commonly, courts allow such searches when they are necessary to prevent the destruction of evidence.  In other words, imagine that a police officer has probable cause to believe that there are drugs in the back of a car.  If the officer does not search the car, the driver can very easily drive away and get rid of the drugs, thus destroying the evidence of the crime.  This leads us to ask whether the planting of the GPS is justifiable under this logic.

Here, too, I would argue that the answer is “no.”  We have no reason to believe that the police officer had to place the GPS when he did.  There is no reason to think that he could not wait to get a warrant.  The police presumably know where the drug dealer lives and could find his car again after they got a warrant.  For this reason, there is no emergency that requires the police to place the GPS without first obtaining a warrant.

Thus, we can see that it was illegal for the officer to plant the GPS.  Any information from the GPS is illegal and evidence gained on the basis of that information is “fruit from the poisonous tree.”