Italian Prime Minister Matteo Renzi kept his promise to resign from office after losing a constitutional referendum tied to his administration Sunday, opening the door for the growing populist Five Star Movement (M5S) to move into Italy’s political driver’s seat.

Sunday’s important referendum marks the third major populist victory worldwide after the Brexit vote in June and Donald Trump’s triumph last month. The resounding defeat of the measure—60 percent to 40 percent—also marked an unprecedented voter turnout, as more than 65 percent of eligible Italians showed up at the ballot box.

As with the cases of Brexit and Trump, the populist movement in Italy is hard to pigeonhole in categories of left and right or conservative and liberal. In many ways, it is easier to define by what it is not rather than what it is. Italian populism sees itself as Euro-skeptic, anti-establishment (whether left or right) and anti-corruption.

Italy’s Five Star Movement, the standard-bearer of Italian populism, was so-named because of the five causes it originally espoused: public water, improved transportation, sustainable development, free internet access and environmentalism. These are hardly right-wing causes, but nor are they the agenda of the Italian establishment.

After M5S scored major victories last June, winning mayoral races in Rome and Turin as well as over a dozen other cities, it established itself as Italy’s most significant opposition force. Its rise in popularity has continued unabated ever since.

“The propaganda of the regime and all its lies are the first losers of this referendum,” said Beppe Grillo, the founder and leader of M5S. “Times have changed.”

Virginia Raggi, Rome’s M5S mayor, called the referendum outcome a victory for democracy, tweeting that “our revolution will not stop, in Rome and in Italy.”

#HaVintoLaDemocrazia Hanno vinto gli italiani. Ora ricostruiamo il Paese. La nostra rivoluzione non si ferma, a Roma e in Italia. — Virginia Raggi (@virginiaraggi) December 5, 2016

Despite his early reputation as a reformer, during his two-and-a-half-year rule, Matteo Renzi became more and more identified with the establishment and especially beholden to the European Union (EU) with its gross mismanagement of the migrant crisis, a position that cost him popularity. His inability to lift Italy out of the economic gutter further sullied his political image.

The autocratic Prime Minister issued an edict in June opening the door for civil unions in Italy, bypassing parliamentary debate and unilaterally settling the question outside of the democratic political process. This measure earned him the ire of Italy’s powerful pro-family movement and enduring suspicion among those who value the rule of law.

The immediate outcome of the Renzi exit is yet to be determined. The Italian President, Sergio Mattarella, may name a caretaker government staffed with technocrats, or he may call for early elections in 2017.

Either way, Renzi’s defeat will further galvanize Italy’s populist movement while also sending signs to other EU nations—such as France—that resistance to the establishment is possible.

Follow Thomas D. Williams on Twitter Follow @tdwilliamsrome