In short, what was nominally a democracy became in his hands government by the first citizen.

With his successors it was different.
More on a level with one another, and each grasping at supremacy, they ended by committing even the conduct of state affairs to the whims of the multitude.

This, as might have been expected in a great and sovereign state, produced a host of blunders, and amongst them the Sicilian expedition; though this failed not so much through a miscalculation of the power of those against whom it was sent, as through a fault in the senders in not taking the best measures afterwards to assist those who had gone out, but choosing rather to occupy themselves with private cabals for the leadership of the commons, by which they not only paralysed operations in the field, but also first introduced civil discord at home.

Yet after losing most of their fleet besides other forces in Sicily, and with faction already dominant in the city, they could still for three years make head against their original adversaries, joined not only by the Sicilians, but also by their own allies nearly all in revolt, and at last by the King's son, Cyrus, who furnished the funds for the Peloponnesian navy.

Nor did they finally succumb till they fell the victims of their own intestine disorders.
So superfluously abundant were the resources from which the genius of Pericles foresaw an easy triumph in the war over the unaided forces of the Peloponnesians.
During the same summer the Lacedaemonians and their allies made an expedition with a hundred ships against Zacynthus, an island lying off the coast of Elis, peopled by a colony of Achaeans from Peloponnese, and in alliance with Athens.