Reasonable cause is a standard of proof. It is applied to a set of facts or actions to prove whether a reasonable person would have come to the same conclusion or acted in the same way given the totality of the circumstances. The standard is part of the tests applied by U.S. courts to police action in criminal matters but has also been applied in certain civil contexts.
The U.S. Supreme Court is particularly concerned with the preservation of constitutional rights when civilians are confronted with police action. One main concern has been the issue of a police officer’s right to stop an ordinary citizen to determine if he has been involved in a crime. The court has established probable cause and reasonable cause as the two legal standards of proof, or tests, to be applied to the circumstances of a police stop.
Probable cause is the higher standard and applies to actual arrests and warrants. Reasonable cause is the lesser standard that allows a police officer to stop and briefly detain a citizen if he has reasonable cause to suspect that the person has been or is about to be involved in a crime. This definition allows judges and jurors to determine the legality of the stop. Judges and jurors are asked to determine if a reasonable person of ordinary intelligence, when faced with the same set of circumstances as the police officer, would come to the conclusion that the citizen needed to be stopped.
If the court determines that a reasonable person would not have had enough cause to suspect the citizen of anything illegal, the stop will be judged improper. This type of ruling can form the basis of a citizen filing a civil lawsuit against the police department for damages, usually concerning embarrassment and emotional distress. As a result, many jurisdictions require officers to document and substantiate stops with particularity.
Criminal law is not the only context where a reasonable cause standard can be applied. For example, the U.S. Internal Revenue Service (IRS) uses this standard when a person asks for relief from civil penalties for late or incorrect filing of tax returns. Administrative officers and judges at the IRS review the totality of the circumstances and determine whether there was reasonable cause for the person to have committed the infraction. Reasonableness is considered based on the actions of the ordinary person, and if the IRS thinks the ordinary person, when faced with the same circumstances, would have submitted the offending tax return, it will rescind the fees and penalties associated with the offense.