A reexamination of what trust-busting meant in the Warren Court era, through the prism of the background and character of Justices Black and Douglas, and the decisions they wrote. The article emphasizes their advocacy for a simple and pragmatic antitrust jurisprudence, and in that way explores an urgent topic today: has modern antitrust’s focus on calculable predictions of price effects unduly hampered the law’s ability to protect and foster competition? The article reminds us that current debates mirror questions that have been posed and answered before.