If I am approached by an officer who says he has a warrant do they have to show me it?

An arrest warrant is different than a search warrant.  If there is an active arrest warrant and a law enforcement confirms it before arresting you, the law enforcement officer is allowed to make the arrest (even if the officer is not in possession of the warrant at the time).   However, the law enforcement officer/s is/are not allowed to question you after the arrest without first advising you of your Miranda rights (i.e., right to remain silent and have an attorney present for any questioning).  If you are in custody and questioned by law enforcement, without first being advised of your Miranda rights, it does not make the case go away.  However, it would allow your attorney to file a motion to suppress anything you said in response to such questioning.  That, of course, is assuming the officers admit they questioned you without first giving you your Miranda rights.  If the officers claim you were given your rights (contrary to what you claim), it will be up to the judge to decide whom to believe. Be careful.  Even if you are in custody, if you begin to talk and provide information to the law enforcement officers on your own (i.e., without being questioned), anything you say can be used against you even if you were not given your Miranda rights.  Also, if after being given your Miranda rights, you consent to answer questions and talk to law enforcement officers, anything you say can be used against you.  However, you have the right to terminate the questioning at any time. Also, if you have not been taken into custody, but are being questioned, it is up to you to decide whether to answer questions unless you have been subpoenaed for the purpose of questioning.  If that happens, I urge you to contact an attorney who can explain your options and possible repercussions of each option.  They can be devastating.  You need to know your rights in that event.  They are different than your Miranda rights.