I just happen to be prepping the June 5 news today. I had skipped that item in my initial survey, but I went back and added it to the list.
So John Breckinridge (2nd in the electoral college/ all his States seceded)
Was made Senator for Kentucky on March 4 1861.
He will be officially expelled on December 4 1861 for treason for joining the rebellious democrats as a Major General.
So as of June 4th, he has been in office for 3 months. He and his cohorts are actively pushing to get Kentucky to secede.
(In office March 4, 1861 – December 4, 1861)