The MCM is the United States Manual for Courts Martial. Article 116 deals with Riot or breach of peace, and states the following:
Any person subject to this chapter who causes or participates in any riot or breach of the peace shall be punished as a court-martial may direct.”
The MCM then offers crystal clear definitions of those 2 terms, which follow.
Riot (MCM definition)
““Riot” is a tumultuous disturbance of the peace by three or more persons assembled together in furtherance of a common purpose to execute some enterprise of a private nature by concerted action against anyone who might oppose them, committed in such a violent and turbulent manner as to cause or be calculated to cause public terror. The gravamen of the offense of riot is terrorization of the public. It is immaterial whether the act intended was lawful. Furthermore, it is not necessary that the common purpose be determined before the assembly. It is sufficient if the assembly begins to execute in a tumultuous manner a common purpose formed after it assembled.”
Breach of the peace (MCM definition)
“A “breach of the peace” is an unlawful disturbance of the peace by an outward demonstration of a violent or turbulent nature. The acts or conduct contemplated by this article are those which disturb the public tranquility or impinge upon the peace and good order to which the community is entitled. Engaging in an affray and unlawful discharge of firearms in a public street are examples of conduct which may constitute a breach of the peace. Loud speech and unruly conduct may also constitute a breach of the peace by the speaker. A speaker may also be guilty of causing a breach of the peace if the speaker uses language which can reasonably be expected to produce a violent or turbulent response and a breach of the peace results. The fact that the words are true or used under provocation is not a defense, nor is tumultuous conduct excusable because incited by others.”
The definitions above, in addition to being crystal f***ing clear, apply to members of the United States military.