LOUISVILLE, Ky., Aug. 13 — Improbable as it sounds, the first major test of President Bush's vulnerability on the weak economy may come this November in a state that he won handily in 2000, where his favorable ratings are still high and where Republicans hold seven of eight Congressional seats. No one said Kentucky politics was predictable. With a tenacity that has surprised his opponent and some supporters, the Democratic candidate for governor, Attorney General Ben Chandler, has attacked Mr. Bush's stewardship of the economy, contending that Republican policies have drained Kentucky of 56,000 jobs, aided the wealthy at the...