With the nominating conventions at hand, John McCain and Barack Obama are campaigning hard, despite competition from the Beijing Olympics. What's the impact of Russia's invasion of Georgia? Will the Vice Presidential selections make a difference? A new poll by John Zogby for the Reuters news service shows McCain up by five points. Two others show a virtual dead heat. They are the Los Angeles Times/Bloomberg poll and a survey by the Pew Research Center, where Andrew Kohut is President.