ATHENS — When the authorities detained a former defense minister here last month pending trial, many Greeks found it cause for celebration, a rare case of a “big fish” meeting justice in a political culture widely seen as rife with corruption.

Prosecutors accuse the former defense minister, Akis Tsochatzopoulos, 73, a founding member of the Socialist Party and the highest-ranking Greek official ever to be detained on corruption charges, of pocketing at least $26 million in kickbacks for Greece’s purchase of submarines and missile systems and funneling the money through offshore accounts to buy property.

The unrest here that has occasionally exploded into the streets — and is expected to redraw the political landscape in Sunday’s national elections — is usually portrayed as a reaction to the grinding austerity measures imposed on the country by its international creditors. But for many Greeks, corruption is every bit as emotional an issue as the wage cuts and tax increases that have savaged their standard of living. Indeed, to many here, the two are inextricably linked.

The case of Mr. Tsochatzopoulos (pronounced zok-at-ZOP-ou-los) marks the rise — and perhaps fall — of a political culture that has dominated Greece for decades, in which alternating Socialist and center-right New Democracy governments helped spread the spoils and, critics say, the corruption, during the boom years. That system helped drive up Greece’s public debt to the point that it was forced to seek a foreign bailout in 2010.