I believe a “card” in this case is probably a “ballot”. but I was simply reproducing what I was reading in the media.
.. and just as I am typing this, Pajama Boy just dropped BIG from 50.3 to 48.6. It's over until June for that little prig, and then his five minutes of fame as the Dim's BIG HOPE is probably OVER! Back to the footy pajamas in his mom's basement.