On March 17, 2011 the conductor Riccardo Muti stood in the orchestra pit at the Teatro dell’Opera di Roma and, in the presence of the Italian Prime Minister, Silvio Berlusconi and the Italian President, Giorgio Napolitano, denounced the Italian government’s cuts to funding for the arts and culture. He then invited the entire audience to join the opera’s chorus in an encore of Va’ Pensiero, the hymn of the Hebrew slaves in Nabucco, to protest the cuts. Within two days of that sing-a-long, the Italian government reversed the course it set more than ten months before and agreed to a tax that would be used to restore funds to the arts and culture budget. In this article, I trace how and why those acts of protest in Italy developed, succeeded, and then were appropriated by transnational activists interested in encouraging popular constitutionalism. Because that entire process made considerable use of Facebook, blogs, YouTube, and Twitter, this case study simultaneously explores how a popular protest became a successful expression of popular constitutionalism and considers how the messages of that protest evolved across a transnational public sphere that encompassed Web 2.0.