The Kerry campaign is calling on a heavy hitter from its bench: Former President Bill Clinton plans to hit the trail for the Democratic presidential hopeful Monday in the battleground state of Pennsylvania. "I'm going out tomorrow," Clinton told ABC News' Diane Sawyer today in an exclusive interview airing today on "World News Tonight," Monday on "Good Morning America," and Thursday on "Primetime." Both campaigns are relying on star power in the final days. The Bush campaign has California Gov. Arnold Schwarzenegger stumping for the president in Ohio this week. Clinton, who recently had heart bypass surgery, said he did...