AbstractIn debates about executive branch authority and policy innovation, scholars have focused on two overarching relationships—horizontal tension between the president and Congress and the vertical interplay of federal and state authority. However, these debates have overlooked the role of frontline bureaucratic officials in advancing the laws they administer. This Article looks to immigration law—in which lower-level federal officers exercise discretion delegated down throughout federal agencies—to identify how bottom-up agency influences can inform categorical, across-the-board executive branch policy. In this Article, I argue that decisions by frontline officers can and should be better harnessed to pair local laboratories of executive experimentation with opportunities for interchange throughout various levels of the administrative bureaucracy. Notwithstanding the predominant (and often accurate) view that on-the-ground enforcers resist innovation, many frontline immigration officers have demonstrated willingness, and an ability, to put their discretion toward creative ends. By exploring the interplay between bottom-up and top-down policymaking, this Article provides a useful counterweight to a number of conventional theories regarding presidential administration, offering insights into debates about agency design and administrative constitutionalism. The relationship between on-theground enforcement and across-the-board executive action can also lend greater legitimacy to the Obama administration’s deferred action programs—both in the federal courts and the court of public opinion.