This is the classic mid-American clam chowder, not to be confused with New England’s version. So controversial was the inclusion of tomatoes to New Englanders that a piece of legislation attempting to ban tomatoes from any true chowder was once introduced in Maine. Fresh clams taste great in the chowder, and leaving them in the shell provides a dramatic presentation. In the interest of time, you can substitute 1 cup canned clam meat and an additional 3/4 cup bottled clam juice for the fresh clam and juice.
From the CIA's cookbook, Gourmet Meals in Minutes.