Blog Post  Massachusetts Declaration of Rights – Article 21

Article 21 (1780)

The freedom of deliberation, speech and debate, in either house of the legislature, is so essential to the rights of the people, that it cannot be the foundation of any accusation or prosecution, action or complaint, in any other court or place whatsoever.

Precedents

English Bill of Rights (1689):

[T]he freedom of speech and debates or proceedings in Parliament ought not to be impeached or questioned in any court or place out of Parliament.
 

Article 8, Maryland Declaration of Rights, Adopted November 11, 1776, Delegates of Maryland in Free and Full Convention Assembled:

That freedom of speech and debates, or proceedings in the Legislature, ought not to be impeached in any other court or judicature.