Can a cop arrest someone for illegal substances found without probable cause?

Question

If a policeman searches someone's car WITHOUT probable cause or a warrant (say they're just looking for something to arrest someone for, for example) and happens to find something like illegal drugs or weapons, are they allowed to arrest the suspect for that? Or would the exclusionary rule apply to the evidence since it was obtained without probable cause, forcing them to ignore it? If they are forced to ignore it, is there any scenario in which anything they find without a warrant could be used to arrest someone?

Answer 1

Probable Cause is only an avenue by which a police officer can try to engage with a private area. In the question's wording, the police officer is searching without specific probable cause, which means that the search had to be condoned by the occupant/owner. In any case, yes, if something illegal is found, the person can be arrested for it.

Even more than this, I believe that the focus on probable cause may be a little misguided. The police require only one thing to initiate a search, and that is reasonable suspicion (Terry vs. Ohio). In reality, this gives police officers a huge amount of power and leeway in how they engage citizens.

In regards to the exclusionary rule, the evidence would have to have been obtained by breaking the law or violating the rights of the individual in question to apply. At least in the case as written, no rights were violated. You have the right of it in the final question, if something is found illegally, it cannot be utilized as evidence to arrest someone. An example of this would be a police officer breaking into someone's car and rifling through their glove box to find a dime bag of marijuana.