Over the past 15 years, people in the United States—and dissidents in particular—have witnessed a steady escalation of the National Security State, including invasive surveillance and infiltration, indiscriminate police violence, and unlawful arrests. These concerted efforts to spy on Americans and undermine meaningful social change are greatly enhanced by the coordination of numerous local, state, and federal agencies often operating at the behest of private corporations. Crashing the Party shows how these developments—normally associated with the realities of a post–9/11 world—were already being set in motion during the Republican National Convention protests in 2000. It also documents how, in response, dissidents confronted new forms of political repression by pushing legal boundaries and establishing new models of collective resistance. Crashing the Party explains how the events of 2000 acted as a testing ground in which Philadelphia Police Commissioner John Timoney was able to develop repressive methods of policing that have been used extensively across the U.S. ever since. At the same time, these events also provided a laboratory for the radical, innovative, and confrontational forms of legal support carried out by R2K Legal, a defendant-led collective that raised unprecedented amounts of money for legal defense, used a unique form of court solidarity to overcome hundreds of serious charges, and implemented a PR campaign that turned the tide of public opinion in favor of dissidents. While much has been written about the global-justice era of struggle, little attention has been paid to the legal struggles of the period or the renewed use of solidarity tactics in jail and the courtroom that made them possible. By analyzing the successes and failures of these tactics, Crashing the Party offers rare insight into the mechanics and concrete effects of such resistance. In this way, it is an invaluable resource for those seeking to confront today’s renewed counterintelligence tactics.