This chapter examines the relationship between print, popular political mobilization (crowd action, street politics, and mass petitioning), and the high politics of the Long Parliament. It examines the street demonstrations and crowd actions of winter 1641–2, focusing on the ways that print was used to organize, propagandize, or channel mass crowd activity and the ways those popular political mobilizations were inseparably linked to maneuver in parliament itself. The contested politics of the period—and in particular battles between the two houses of parliament over efforts to protect against a royal reaction—led to significant ideological escalation, as some backers of parliament began to question the function of the peerage, the negative voice of the king, and other constitutional conventions. The printed expression of these radical political impulses, coupled with the threat of violence from the crowds, fed a process of polarization, contributing to a growing royalist countermovement.