Cook bacon in a large Dutch oven over medium heat 5 minutes or until crisp. Remove bacon from pan, reserving 1 teaspoon drippings in pan. Add onion to drippings in pan; cook 5 minutes or until browned. Add 1 cup clam juice, scraping pan to loosen browned bits. Add remaining 1 cup clam juice and broth; bring to a boil. Add potato; simmer 10 minutes.
Add corn and clams to pan; bring to a boil. Reduce heat, and simmer 5 minutes or until shells open. Remove from heat; stir in buttermilk and remaining ingredients. Sprinkle with bacon.