Sen. John McCain (R-Ariz.) on Sunday expressed opposition to possible GOP efforts to filibuster a Senate gun-control measure, saying he did not “understand” the move to block debate. “I don’t understand it,” said McCain on CBS’s “Face the Nation.” “The purpose of the United States Senate is to debate and to vote and to let the people know where we stand.” “What are we afraid of? Why would we not want… if this issue is as important as all of us think it is, why not take it to one of the world’s greatest deliberative bodies… A number of GOP...