Public defenders are asked to do more with less: representing clients deserving of adequate counsel while facing overwhelming caseloads and scarce resources. Although artificial intelligence (AI) is often promoted as a means of relieving administrative and cognitive burdens, legal AI research rarely engages with the everyday realities of public defense work. Drawing on in-depth, semi-structured interviews with fourteen public defense professionals across the United States, we identify work-intensive tasks most amenable to AI assistance and the ethical constraints involved in legal representation. We develop a comprehensive task-level map of public defense work, dividing it into five domains to clarify where AI can and cannot contribute: evidence investigation, legal research & writing, client communication, courtroom representation, and defense strategy. Interviewees consistently identified evidence investigation, such as reviewing large volumes of digital records, as the area with the greatest potential for AI support. AI was viewed as having more limited roles in legal research and client communication, and as least compatible with courtroom representation and defense strategy. We find that AI adoption is constrained by costs, restrictive office norms, confidentiality risks, and unsatisfactory tool quality. Our interviewees emphasize safeguards for responsible use, including mandatory human verification, limits on overreliance, and the preservation of relational aspects of lawyering. Building on these findings, we outline a research agenda that promotes equitable access to justice by prioritizing open science, building domain-specific datasets and evaluation, and incorporating frontline practitioners' perspectives into system development.

翻译：公设辩护人被要求以更少的资源做更多的事：在承担过重案件负荷和资源匮乏的同时，为值得充分辩护的当事人提供代理服务。尽管人工智能常被宣扬为减轻行政与认知负担的手段，但法律AI研究鲜少触及公设辩护工作的日常现实。通过对全美十四名公设辩护专业人士进行深度半结构化访谈，我们识别出最适宜AI辅助的高强度任务及其在法律代理中的伦理约束。我们绘制了公设辩护工作的全面任务层级图谱，将其划分为五个领域以明确AI的适用边界：证据调查、法律研究与文书、客户沟通、法庭代理及辩护策略。受访者一致认为，证据调查（如审查大量电子记录）是AI最具支持潜力的领域；AI在法律研究与客户沟通中的作用较为有限，与法庭代理和辩护策略的兼容性最低。我们发现，AI的应用受限于成本、严格的办公室规范、保密风险及工具质量不足。受访者强调负责任的AI使用需设立保障措施，包括强制人工核验、限制过度依赖，以及维护律师执业中的人际关系要素。基于上述发现，我们提出一项研究议程，通过优先发展开放科学、构建领域特定数据集与评估体系、将一线从业者视角纳入系统开发，以促进司法公正的平等实现。