Before every election, the Post-Gazette routinely sends letters to the candidates seeking material for the Voters Guide. Back in March, as part of that process for the primary, the newspaper sent a letter to Rick Santorum at his home address, at least the one that he claims. Back from Penn Hills came the letter with a sticker from the U.S. Postal Service checked as "Not Deliverable As Addressed -- Unable To Forward." That is all you need to know about the nasty dispute between the Republican Sen. Santorum and his Democratic opponent, Bob Casey Jr., in the November election. The...