Probable Cause and Motor Vehicles

I don't know if you know it or not, but our police can not just stop a motorist without probable cause to do so. This means that some kind of traffic law must have been broken. I will not talk about DUI checkpoints; that is a subject for another Blog.
So, it must appear that some wrong has occurred: bad driving, weaving in and out, speeding, an equipment violation, expired stickers, etc., the list goes on. Once that happens, the officer can stop the vehicle. Then, if he sees illegal activity, he can carry out an arrest and subsequent search.
Recently, I tried a case defending a young man who was charged with carrying a concealed weapon, a pistol. Actually, it was underneath the driver's seat.
The facts of the stop were these. Police get a report of shots fired at a party at a certain residence. A police car is sent to the house. Just as the officer arrives, my client is driving away from the residence. No bad driving, just leaving. The officer stops my client's car, and searched the car supposedly with my client's permission. The officer finds a pistol and arrests my client. However, I pointed out to the Judge that there was no probable cause for the original stop, therefore a bad search, even with permission. Accordingly, the case was dismissed.
We here in the United States are entitled to go about our daily affairs without be stopped by police officers, unless there is probable cause. No police officer hunches or maybes.