Americans owe many rights that we take for granted to men who, centuries ago, codified them in the U.S. Constitution. One of those, "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures," is in the Fourth Amendment. The founding fathers went on to say that "no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be searched."

If that sounds familiar from "Law and Order" reruns, it's because terms like "probable cause" are key to the concept of American justice. There are instances, however, where a warrant isn't necessary for authorities to arrest someone, to conduct a search or to seize potential evidence.

Warrantless Arrests and Detentions

If officers witness a crime being committed in public or have a reasonable belief that someone is about to or has committed a crime, they can arrest that person without obtaining an arrest warrant. This reasonable belief can't just be a suspicion or hunch.

Officers can detain people temporarily, however, based on a "reasonable suspicion" of illegal activity. They may do this to buy them time while obtaining an arrest warrant. They must, however, show probable cause to a judge to get that warrant.

Warrantless Searches and Seizures

Before officers can search a home, vehicle or other area and seize items from the location, they must have probable cause to believe a crime was committed there and/or the location contains evidence of a crime. If they obtain a warrant, it must specify what areas can be searched and what items can be seized.

However, there are instances where a warrant isn't necessary. For example, if officers believe the evidence will be lost if they don't take it, there's a safety threat or the search is part of an arrest, they may legally search an area without a warrant. They may also search a location if someone there provides consent. However, it can be a matter of debate who has the authority to give that permission if police come to a home. Further, a warrant isn't required to seize property that is "in plain sight" or reasonably believed to be evidence.

Anyone who believes that officers did not have the right to a warrantless arrest, search and/or seizure based on the situation can make that case in court. This can potentially lead to some or all charges being dropped. An experienced criminal defense attorney can work to do that. Therefore, it's essential to recount the circumstances surrounding your arrest to your attorney.