You know, the saddest thing about this whole deal is that Craig, a US Senator, did not know what was in the constitution he was sworn to uphold.
Article 1, Section 6
They {Senators and Reps} shall in all cases, except treason, felony and breach of the peace, be privileged from arrest during their attendance at the session of their respective Houses, and in going to and returning from the same; and for any speech or debate in either House, they shall not be questioned in any other place.
As he was returning to Idaho from a session of the Senate, he was unarrestable, let alone convictable.
All Craig needed to quote the Constitution and he would have been free.
The only recourse for the Minn. police would have been to bring this charge to the Senate.