Abstract: This article takes an "abnormal petition" incident as a case study to explore the changes in the responsibility boundary of grassroots governments and the emergence of relevant action strategies. The research finds that grassroots governments have a dual role orientation of "business department" and "political unit", and their respective behavioral logics are also different. The former suits for a rational bureaucracy, and its design of clear task boundaries causes the ambiguity of the responsibility boundaries of grassroots governments in practice, leaving institutional space for their risk avoidance strategies. The latter applies to the political integration, and its blurred task boundary design in fact forces grassroots governments to re-clarify their responsibility boundaries and enforce their sense of responsibility. Affected by the logic of the two systems, the responsibility boundary of grassroots governments exhibits the characteristic of "fluidity", and governments' behaviors have also shifted from "risk avoidance" to "risk taking". Rational bureaucracy and political integration determine the dual role orientation of "business-politics" of grassroots governments, which in turn affects the fluidity of the responsibility boundary. Therefore, changes of events in the governance context become the trigger mechanism. In this case study, the incident was initially just a homestead dispute. However, according to the logic of rational bureaucracy, the local government avoided the responsibility to resolve the dispute by diverting the case to the Bureau of Justice and the Bureau of Health. When the petitioner's appeal to the Bureaus failed, her journey of petitioning began. Since the incident has now transformed from an administrative incident to a petition case, the responsibility boundary of the local government has changed, and the political integration system began to play a major role. As a result, the local government takes on the responsibility of dealing with petition cases using tactics of appeasement, strict pressure, and downward responsibility transfer. This article constructed the phrase of "fluid responsibility boundary" and used it as an analytical framework, emphasizing the dual roles of grassroots governments and situational change in shaping their behavior. The study contributes to the dialogues and development of research on grassroots government responsibility.

Key words: boundary of responsibility of grassroots government, rational bureaucracy, political integration system, business departments, political units