The Sicilian Expedition is sometimes mentioned as a war between somewhat-democratic states. Some democratic peace researchers have excluded the states in Ancient Greece because of the limited franchise and the use of allotment to select many government leaders. As noted earlier, Weart classifies Athens as a democracy and argues that the war was actually an example of a war between a democracy and an oligarchy. However, he also states, "The possibility that the Athenians were wrong suggests a qualification to our rule. Instead of saying that well-established democracies do not make war on their own kind, perhaps we should say that they do not make war on other states they "perceive" to be democracies." Critics argue that there is no ancient evidence for this perception and that the major source on Syracuse democracy is Thucydides, an Athenian. Weart states Aristotle, an Athenian metic, the only scholar who ever possessed the documents required to study the constitution of Syracuse, carefully avoided calling Syracuse a democracy. One of the main reasons for the Sicilian Expedition was that Syracuse was reported to have violent factional strife. Help from an inside group was essential since the Greeks lacked effective siege machinery, and the expedition was ill-suited for the alternative, a long wait to starve the defenders. In every other known case of cities being betrayed to an Athenian army, it was by a democratic faction. Furthermore, scholars have argued that Thucydides disliked democracy, which affected his descriptions and evaluations. Weart's argument on the Sicilian Expedition is similar to the position of the prominent scholar G.E.M. de Ste. Croix.