This chapter examines the effects of party systems and media access on public attitudes and government decisions regarding coalition joining in the periods leading up to and immediately following the initiations of two distinct multinational military conflicts: Operation Iraqi Freedom in Iraq and Operation Enduring Freedom in Afghanistan. Drawing on cross-national data on public support for the Iraq War and Afghanistan invasion and the decisions of countries to contribute troops to the coalitions that the United States sought to assemble in both conflicts, the chapter shows that the quality and flow of information from whistleblowers mediates public support for intervention and leaders' responsiveness to public sentiment. Countries with more political parties were more likely to have populations opposed to the wars and to contribute fewer troops to the coalitions as their access to mass media increased. In contrast, in states with fewer parties, increased media access is associated with lower opposition to the wars and stronger troop commitments.