The Federal Anti-Riot Law

by Jody Ballew

This links to an online source of the code (18 USC 2101 - Sec. 2101. Riots) used to justify Madison's arrest for twittering. 

Here is an excerpt of that code:

(a) Whoever travels in interstate or foreign commerce or uses any facility of interstate or foreign commerce, including, but not limited to, the mail, telegraph, telephone, radio, or television, with intent - (1) to incite a riot; or (2) to organize, promote, encourage, participate in, or carry on a riot; or (3) to commit any act of violence in furtherance of a riot; or (4) to aid or abet any person in inciting or participating in or carrying on a riot or committing any act of violence in furtherance of a riot; and who either during the course of any such travel or use or thereafter performs or attempts to perform any other overt act for any purpose specified in subparagraph (A), (B), (C), or (D) of this paragraph - (!1) Shall be fined under this title, or imprisoned not more than five years, or both. (b) In any prosecution under this section, proof that a defendant engaged or attempted to engage in one or more of the overt acts described in subparagraph (A), (B), (C), or (D) of paragraph (1) of subsection (a) (!2) and (1) has traveled in interstate or foreign commerce, or (2) has use of or used any facility of interstate or foreign commerce, including but not limited to, mail, telegraph, telephone, radio, or television, to communicate with or broadcast to any person or group of persons prior to such overt acts, such travel or use shall be admissible proof to establish that such defendant traveled in or used such facility of interstate or foreign commerce.