The recent passing of William D. Ruckelshaus has recalled and re-invited comparisons between the Trump and Nixon presidencies. Although Ruckelshaus might be most widely remembered for the “Saturday Night Massacre,” a review of his career in the Nixon and Reagan Administrations demonstrates a through-line of sound administration and independent regulatory leadership, at times in contrast to or in spite of his political environment. This Article explores the course of Ruckelshaus’ career in environmental regulation, focusing on his two terms as Administrator of EPA, in order to better understand the ways in which administrative and regulatory agencies gain, squander, and restore the most basic currency of government: credibility. Drawing from a number of unpublished primary materials, it fi nds that regulatory programs independent of presidential pressure are necessary to legitimate and credible executive government, and argues that this independence is lacking in the centralized power structure of the current Administration.