It was not the Democrats but a group of discontented generals led by Leopoldo O'Donnell who successfully revolted in 1854. They were prepared to sacrifice the dynasty because the queen and her mother favoured a rigid court conservatism that effectively excluded them from influence.
The rebellious military oligarchs were forced to call in civilian and radical support. This turned their pronunciamiento into a mild revolution. Isabella survived only through Espartero's political timidity. Unprepared to accept the backing of the Democrats as the "George Washington of Spain," he accepted an alliance with O'Donnell, who was determined to arrest the drift to radicalism. In 1856 he broke with Espartero, defeated a demonstration in his favour, and dissolved the National Militia, the instrument of the left-wing Progressives. The radical thrust was thus defeated.