His repeated criticism of nationalism in Greece and in the Republic of Cyprus has earned him the opprobrium of key nationalist figures in both countries, and he has been repeatedly attacked in the conservative Greek and Cypriot press and by ultra-nationalist political parties (inter alia in the Greek Parliament) and organizations in Greece and Cyprus from mid-1990s until today (see e.g.Greek Helsinki Monitor, press release, 2 May 2009.
[9][12] Heraclides has also argued that the mass killings and expulsions of Greeks in 1922, committed by the Kemalist government, was not a genocide and instead ethnic cleansing.
For example, he said that the Burning of Smyrna wasn't an act of genocide because "it had been preceded (and caused) by a regular war between the Greek army and Kemal's nationalist forces.
[13] Historian Erik Sjöberg explicitly criticized these assertions, stating that: "Heraclides' core argument was problematic, resting as it did in a somewhat misguided assumption of war and genocide as mutually excluding".
[14] He has written eleven books in English and twenty in Greek, including:[15] His main political contributions to date are with regard to intervention in secessionist conflicts,[16] the reasons for separatism,[17] secession and self-determination,[18] human rights norm-setting in the CSCE process,[19] the Cyprus problem,[20] the Greek-Turkish conflict in the Aegean [21] and the history of humanitarian intervention.