Again, I want to make it clear that I am not a lawyer, and that neither this comment nor the article is legal advise. Also, definitions and laws vary by jurisdiction.

Generally, a “breach of the peace” covers most misdemeanours. So for example, it a misdemeanor crime in Arizona to trespass on private property. If you personally see someone trespassing, you could technically arrest them. However, since it is only a misdemeanor, you can go find a person and arrest them, because your friend tells you he saw that person trespassing earlier.

Here is a definition for you: http://legal-dictionary.thefreedictionary.com/Breach+of+Peace

Nice article and summary of the law. I am specifically interested in your opinion on this statement:

“in his presence committed a misdemeanor amounting to a breach of the peace”

Clearly, it doesn’t have to be a felony if you witness the crime but how does the law interpret “breach of the peace?”