The Volokh Conspiracy - The Arrest Clause:

Reader James Hobson passes along a thought from the Sun Valley Idaho Blog:

If [Senator Craig] had been a better student of the U.S. Constitution, his arrest may never happened at all, and if the U.S. Constitution is followed, as of course it should be, the senator’s arrest and guilty plea will have to be vacated.

This is because the Constitution, in a straightforward and unambiguous manner, states in Article 1, Section 6 that "Senators and Representatives shall be privileged from arrest during their attendance at the session of their respective Houses, and in going to and returning from the same." ... The only exceptions are for treason, felony and breach of peace, and the senator, of course, was charged with a misdemeanor.

Since the senator was on his way to Washington, and did in fact cast a vote on the evening of the day on which he was arrested, his arrest and subsequent questioning were, technically speaking, unconstitutional.

Nice idea, but no dice. The Supreme Court's decision in Williamson v. United States (1908) holds that "the term 'treason, felony, and breach of the peace,' as used in the constitutional provision relied upon, excepts from the operation of the privilege all criminal offenses"; the Arrest Clause thus applies only to arrest in civil cases, a practice that apparently was not uncommon at the timing of the Framing. The sources Williamson points to, including Justice Story's respected 1833 treatise on the Constitution, seem to bear this out:

§ 862. The exception to the privilege is, that it shall not extend to "treason, felony, or breach of the peace." These words are the same as those, in which the exception to the privilege of parliament is usually expressed at the common law, and was doubtless borrowed from that source. Now, as all crimes are offences against the peace, the phrase "breach of the peace" would seem to extend to all indictable offences, as well those, which are, in fact, attended with force and violence, as those, which are only constructive breaches of the peace of the government, inasmuch as they violate its good order....

So no help to Sen. Craig here.

	[Eugene Volokh, September 10, 2007 at 3:59pm] Trackbacks The Arrest Clause: Reader James Hobson passes along a thought from the Sun Valley Idaho Blog: If [Senator Craig] had been a better student of the U.S. Constitution, his arrest may never happened at all, and if the U.S. Constitution is followed, as of course it should be, the senator’s arrest and guilty plea will have to be vacated. This is because the Constitution, in a straightforward and unambiguous manner, states in Article 1, Section 6 that "Senators and Representatives shall be privileged from arrest during their attendance at the session of their respective Houses, and in going to and returning from the same." ... The only exceptions are for treason, felony and breach of peace, and the senator, of course, was charged with a misdemeanor. Since the senator was on his way to Washington, and did in fact cast a vote on the evening of the day on which he was arrested, his arrest and subsequent questioning were, technically speaking, unconstitutional. Nice idea, but no dice. The Supreme Court's decision in Williamson v. United States (1908) holds that "the term 'treason, felony, and breach of the peace,' as used in the constitutional provision relied upon, excepts from the operation of the privilege all criminal offenses"; the Arrest Clause thus applies only to arrest in civil cases, a practice that apparently was not uncommon at the timing of the Framing. The sources Williamson points to, including Justice Story's respected 1833 treatise on the Constitution, seem to bear this out: § 862. The exception to the privilege is, that it shall not extend to "treason, felony, or breach of the peace." These words are the same as those, in which the exception to the privilege of parliament is usually expressed at the common law, and was doubtless borrowed from that source. Now, as all crimes are offences against the peace, the phrase "breach of the peace" would seem to extend to all indictable offences, as well those, which are, in fact, attended with force and violence, as those, which are only constructive breaches of the peace of the government, inasmuch as they violate its good order.... So no help to Sen. Craig here.