Some scholars support the democratic peace on probabilistic grounds: since many wars have been fought since democracies first arose, we might expect a proportionate number of wars to have occurred between democracies, if democracies fought each other as freely as other pairs of states; but proponents of democratic peace theory claim that the number is much less than might be expected (Bremer 1992, Bremer 1993, Gelditsch 1992, Doyle 1983[incomplete short citation]). However, opponents of the theory argue this is mistaken and claim there are numerous examples of wars between democracies (Schwartz & Skinner 2002, p. 159).
Historically, cases commonly cited as exceptions include the Sicilian Expedition, the Spanish–American War, and more recently the Kargil War (White 2005). Doyle (1983)[incomplete short citation]) cites the Paquisha War and the Lebanese air force's intervention in the Six-Day War. The total number of cases suggested in the literature is at least 50. The data set Bremer (1993) was using showed one exception, the French-Thai War of 1940; Gleditsch (1995) sees the (somewhat technical) state of war between Finland and UK during World War II, as a special case, which should probably be treated separately: an incidental state of war between democracies during large multi-polar wars (Gowa 1999; Maoz 1997, p. 165). However, the UK did bomb Finland, implying the war was not only on paper. Page Fortna (2004) discusses the 1974 Turkish invasion of Cyprus and the Kargil War as exceptions, finding the latter to be the most significant. However, the status of these countries as being truly democratic is a matter of debate. For instance, in Spain in 1898, two parties alternated in the government in a controlled process known as el turno pacífico, and the caciques, powerful local figures, were used to manipulate election results, and as a result resentment of the system slowly built up over time and important nationalist movements as well as unions started to form. Similarly, the Turkish intervention in Cyprus occurred only after the Cypriot elected government was abolished in a coup sponsored by the military government of Greece.
Limiting the theory to only truly stable and genuine democracies leads to a very restrictive set of highly prosperous nations with little incentive in armed conflict that might harm their economies, in which the theory might be expected to hold virtually by definition.
One advocate of the democratic peace explains that his reason to choose a definition of democracy sufficiently restrictive to exclude all wars between democracies are what "might be disparagingly termed public relations": students and politicians will be more impressed by such a claim than by claims that wars between democracies are less likely (Ray 1998, p. 89).