The McCain-Palin ticket may be locking its huge lead on a crucial voting bloc: church-going Catholics. The development — contained Thursday in a poll by the Pew Research Center and backed by other polls — could be crucial to victory in November. Why? Catholics are the ultimate swing voters and make up as much as one-third the population of battleground states like Ohio, Pennsylvania and Michigan. Moreover, some 40 percent of U.S. Catholics have no affiliation with either party. Republican presidential candidate John McCain now has opened a 16-percentage-point lead over Democratic rival Barack Obama among observant Catholics, according to...