Sedition is a common law offence of long-standing, given the monarchy's historic fear of criticism.
To wit, Osborn described sedition as:
"... publishing verbally or otherwise any words or documents with the intention of exciting disaffection, hatred or contempt against the sovereign, or the government and constitution of the Kingdom, or either house of Parliament, or the administration of justice, or of exciting her Majesty's subjects to attempt, otherwise than by lawful means, the alteration of any matter in church or state, or other exciting feelings of ill will and hostility between different classes of her Majesty's subjects."
In an oft-cited case of 1886, R v Burns (16 Cox's Criminal Cases 355), the court adopted these words:
"Sedition is a comprehensive term, and it embraces all those practices whether by word, deed, or writing, which are calculated to disturb the tranquility of the state, and indeed ignorant persons to endeavor to subvert the government and the laws of the Empire."
Sedition is distinguished from treason in that sedition does not imply any overt act; treason does. As such, sedition precedes treason, treason follows sedition.
Where the sedition is libelous, it is often referred to as seditious libel.
The US Code, at Title 18, §2384 (see also §2385), defines "seditious conspiracy" as:
"If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined under this title or imprisoned not more than twenty years, or both."