Barratry is the improper solicitation of a client done by or on behalf of an attorney and is a criminal offense in most states. The filing of a lawsuit or other legal complaint without the permission of the named plaintiff or complainant may also constitute barratry. And a judge who accepts a bribe in exchange for a favorable decision may be guilty of barratry.

Maintenance refers to improper assistance in prosecuting or defending a lawsuit, provided by someone who has no legitimate interest in the case—also known as meddling in someone else's litigation.

And champerty is an agreement between a litigant and an intermeddler in a lawsuit in which the intermeddler helps the litigant pursue the claim in exchange for receiving part of any settlement or judgment in the litigation.

Laws regarding barratry, maintenance, and champerty vary from state to state and are usually located in a state's statutes—often in the penal code or criminal code. Barratry is illegal in all states, with criminal prosecution and state licensing implications for attorneys who engage in the practice. But the maintenance and champerty doctrines are not recognized in all states.

In Montana, barratry, maintenance, and champerty are addressed under state law. Barratry, which includes the improper solicitation of clients by an attorney and the unauthorized filing of legal actions, is considered an offense and can lead to criminal charges as well as professional disciplinary actions against an attorney. Montana law specifically prohibits attorneys from soliciting business by direct personal contact with a prospective client with whom the attorney has no family or prior professional relationship. Maintenance, defined as the intermeddling in another person's lawsuit without a legitimate interest, and champerty, which involves an agreement to share in the proceeds of litigation, are also recognized concepts in Montana. These practices are generally disfavored as they can lead to frivolous litigation and conflicts of interest. However, the application and enforcement of laws against maintenance and champerty can be complex and may vary based on the specifics of each case. It's important for attorneys to avoid these practices to maintain professional integrity and comply with legal standards.