How dangerous is populism for democracy?

In the 1920s José Ortega y Gasset, an educated and conservative Spanish thinker, observed with increasing concern that liberal regimes, in spite of the fact that they extended suffrage and increased political and social rights, were losing control over their political systems and that the masses were inclined to support extremist political forces. The populist upsurge we have witnessed in the last years could be the symptom, to use Ortega's term, of a new revolt of the masses. The rebellion is directed not so much towards the very essence of the democratic form of government, but rather towards those elites that have failed to share advantages with the people.