
I don't know about Washington, DC law, but in the State of Florida, Battery is basically defined as any unwelcome touch by another.

Soap Box Ravings is shocked that a Democrat Congressman would demand to know the name of his questioner when many of his Democrat peers including President Obama believe the Arizona Immigration Law in which an Arizona police officer will be allowed to ascertain the nationality of people they are dealing with.
Etheridge's behavior makes me believe you have to identify yourself to a Congressman before asking a question, but police officers in Arizona can not ask for your identity.