When, how, and under what conditions can individual legislators affect presidential appointments? Since the early 1900s, the senatorial norm of the blue slip has played a key role in the confirmation process of federal district and appeals court judges, and it is an important aspect of the individual prerogative that characterizes senatorial behavior more broadly. We analyze newly available blue slips, covering the historical period 1933–1960. We show that the blue slip functioned in this era most often to support and expedite nominations, indicating that senators used this device to shape the nominations agenda in this period. Additionally, we analyze the factors that contributed to an individual senator's decision to support or oppose a nominee, or return a blue slip at all, finding that senators were more likely to return positive blue slips when the Judiciary Committee chair was not a coalition ally. We argue that while blue slips did at times provide an early warning for poor nominees, they more often offered a means by which senators ensured that their desired nominees were confirmed swiftly. The positive role of the blue slip demonstrates that this device protected the individual prerogatives of senators, allowing them a degree of agenda-setting authority with regard to nominees in the weak parties era.