Many people at some point in their lives are stopped by the police or have some encounter with the police. It is smart to have at least a basic understanding of your constitutional rights and what to do not do in these situations.
Do Not Consent to Searches
In order for the police to search you they need what is called probable cause. Do not make their job easier to find incriminating evidence. You should never consent to a search, but of course you should also never physically resist one. If asked, simply decline. If pressed about it, simply reply that you want to preserve your rights. Keep in mind even if you know that you don't have anything illegal it still isn't a good idea to consent to search. If you are pulled over in a vehicle, searching can entail you and your family sitting on the side of the road while it is conducted. Searching can also involve possible damage to your vehicle. Additionally if someone else occasionally drives your vehicle, you can never be certain there isn't anything illegal in it. It won't be as easy in court to claim someone else left the contraband in your car and you didn't know about it. Your home is considered to have the greatest Fourth Amendment protection against unreasonable searches. The police would need a warrant if they want to search your home. Unless you consent. The police can search anywhere, including your home if you consent. If police want to search your home then definitely ask to see a warrant.
Ask If You Are Free to Leave
If you are stopped by the police on foot it often feels like you aren't free to leave and end the encounter. You may be surprised, however, how often the prosecutors argue the encounter was voluntary up until the moment the police discovered the illegality at issue. This is important because you have no Fourth Amendment rights concerning a voluntary encounter. The police are able to walk up to anyone and engage in a consensual conversation.
This is why it is always important to ask if you are free to leave. In order for the police to detain you they must have what is called "reasonable articulable suspicion." This suspicion must be more than a hunch. The officer has to have specific reasons why he believes you committed a crime, are about to commit a crime, or criminal activity is afoot. Asking if you are free to leave can immediately end the encounter if the officer knows he doesn't have enough for reasonable suspicion at that juncture. It also helps your case later if there is a basis to suppress evidence against you because the officer detained you without reasonable suspicion.
Do Not Volunteer Information or Make any Admissions
We've all heard of "Miranda Warnings." It is absolutely true that "Anything you say can and will be used against you." But you should also be aware that things you say can and will be used against you before you are even given that warning by the officer. Typically you won't get that warning until you are already under arrest. You still may never get that warning unless an officer is questioning you. Statements you make before being given that warning and before you are arrested are still admissible against you as voluntary statements. It can be incredibly difficult later to win a case when you have volunteered incriminating information.
If You Get Arrested Ask for An Attorney
You could end up in an interrogation room after being arrested. Often the police will give you a Miranda warning form that has several questions on it. The form will ask:
Have You Had Your Rights Read to You?
Do you Understand Your Rights?
Do You Wish to Answer any Questions?
Are you Willing to Answer Questions without an Attorney Present?
You should absolutely not answer any questions. The first thing you should ask for is your attorney. The case law is clear that if you ask for an attorney that ends the interrogation until you are provided one unless you reinitiate the communication. You don't know what the police know. They may not know anything and are depending on you to give them incriminating information to prosecute you. Do not think you can talk your away out of it. You cannot know what information may even be incriminating. Merely acknowledging the location you were at on a particular date may be extremely incriminating. The best course of action by far is to ask for an attorney to stop the interrogation.
The Police can and will lie to you
The ability of the police to lie to you has been repeatedly upheld by Courts. This is another reason why you never agree to any questioning. The police can tell you your friends are all saying you did it. The police can tell you they have your DNA or fingerprints at the crime scene. Undercovers obviously can lie to you about evening being police. Some states have some exceptions on how far the police can go with lying to you but there is a broad spectrum of fibs the police can tell you in order to get you to confess or give them information to assist in prosecuting you or someone else.