a citizen's arrest is not really an arrest in the strictest sense of the word. A citizen's arrest is an arrest a "civilian" can make when a crime is in progress. What Jim is talking about is the the power and authority to arrest someone as he said, "In thier homes, in front of thier friends and family." For crimes they have committed (not necissarily a crime they are commiting at the time.)
also, a citizen's arrest, is not really an arrest perse, because yes, a citizen can, detain and restrain, but cannot "officially," arrest.