The warfare of the Greek city states was limited by their means, lacking military academies, professional officers and standing forces. Small communities fought local wars with levies of citizens, often highly motivated, but precious to the polity, which could not be kept in the field for long. Fruits of victory were modest, and defeat could put the survival of the whole state at risk. Fortification as a passive defensive policy was essential. In offensive warfare, states and coalitions mostly pursued a strategy of opportunism, in which the desirable was subordinated to the attainable. Commanders typically tried to avoid decisive engagements due to the risks involved; they focused their attacks on exposed targets like farmland, small towns, isolated garrisons and unprepared enemy troops. They relied heavily on local dissenters and deserters to guide and facilitate operations. When wealthier states like Corinth, Athens and Syracuse found themselves able to invest in warfare, we clearly see their dissatisfaction with this strategic straitjacket. The rapid development of fleets, extensive fortification networks, standing corps of specialist troops and siege technology allowed these states to dominate their less fortunate neighbours. This gives the lie to old notions that the Greeks preferred their wars to be limited in scope. A state that had much more than the others could disrupt the entire system, as Macedon would eventually show.