Perhaps then we should identify where the line has been drawn before with regard to the denial of Communion. I honestly don't know, and would appreciate it if that discussion was initiated here, or if someone could direct me to that discussion elsewhere on FR.
The Bishops are stating publicly that these politicians, who are calling themselves Catholics in their campaign literature and using their 'Catholicism' on the stump, are causing scandal by presenting themselves for reception of Communion. By their receiving the Body and Blood of Jesus, they are presumably accepting the teachings of the Church, but by voting FOR abortion, and speaking out for the so called 'right to choose', they are being vocal in their defiance of those teachings. The Bishops are simply asking for truth in advertising.