Using a panel data survey in which the second wave was made just before and after the eruption of the anti-austerity protests in Spain, and identifying those who participated in the events thanks to a question in subsequent waves, I leverage quasi-experimental evidence supporting that political protests can substantially alter the perception of political parties on the left-right dimension. I show that leftist citizens who participated in the anti-austerity protests perceived that the center-left incumbent party moved to the center and that this perception remained stable over time. This situation led to an empty political space that could have been exploited by new protest parties willing to capitalize on this crisis of representation. Beyond showing that political protests can quickly alter citizens' perceptions of parties on the left-right dimension, this article suggests that protests can create an empty political space without the emergence of a second dimension of party competition.