This is not true under all circumstances. Congresspersons are arrested from time to time. There is only one situation that I know of where a congressperson cannot be arrested, and I think it has something to do with the congressperson being on his/her way to a session, or maybe to a vote. Of course, this doesn't prevent arrest afterward.
If they are on their way to a vote or if they dont want to be arrested
Arrest from anything except a felony or treason Also they cannot be sued for anything they say while they are on the floor
The reason Congressmen can not be arrested is to stop the Police, the Executvie Branch, from detaining and there by interfering with the voting of the Congress. Imagine if someone with Police authority, President, a Governor, a Mayor, or such, did not want a law to pass in congress. He could simple arrest all of the congressmen who might vote against the President's wishes. Congress would not be able to function if its members were subject arrest. I believe that only Congress can arrest congressmen. Sure the Police might bring an indictment but they cannot arreest and detain the congressmen without Congressional authority. Otherwise Congressmen would be arrested constantly. I also believe the "no hold" arrest policy applies to Governors and State Legislatures. Same problem. If the State of California wanted to pass a law that the Federal Government did not like then the Federal Government would just arrest the Governor so the law could not be signed into being. So, where does this power end? What are the limits? Can the US Marshals arrest Eliot Spitzer on protitution charges and remove or imprison him while he is the Governor of New York State? I don't think they can. It would be too easy for them to remove Governors at will. Will the New York Legislature allow the Eliot Spitzer to remain as their Governor. I hope not.
why yes yes they are
ANY citizen is liable to arrest for an offense. In the US, theoretically, not even the President is immune from arrest by a duly constituted law enforcment officer regardless of WHAT agency they work for.
Yes, DA's (i.e.: prosecutors) are not immune from arrest if they violate any laws.
arrest
Members of Congress are immune from detainment and arrest by law enforcement when traveling to and from, or during the course of their official duties, while in session. This provision was is meant to protect them from delay for petty offenses, so naturally this protection does not extend to high crimes.
Immunity from arrest or parking tickets (except for felonies). Free mail. special pension and retirement.
It is all about the parliamentary privileges of the congressmen which are the privilege from arrest and privilege pf speech and debate.
The possessive form for the noun congressmen is congressmen's.Example:The congressmen's luncheon is scheduled for one o'clock.The congressmen's offices are on the second floor.
Congressmen have a limited privelege against arrest. Except in cases of treason, felony and breach of peace, Congressmen may not be arrested during their attendance at the session of their respective Houses and in going to and returning from same. Article 1, Section 6 Clause 1 of the US Constitution