From 1 May 2012 to 30 April 2018, he served as the first UN Independent Expert on the Promotion of a Democratic and Equitable International Order, appointed by the United Nations Human Rights Council.

[31] De Zayas, in collaboration with Justice Jakob Möller, authored the book United Nations Human Rights Committee Case Law 1977-2008 (2009), published by N. P. Engel Verlag.

[47] In International Humanitarian Law: Origins, edited by John Carey, de Zayas wrote the chapter "Ethnic Cleansing, Applicable Norms, Emerging Jurisprudence, Implementable Remedies".

"[60] In 1975, de Zayas published a study in the Harvard International Law Journal, questioning the legality of the expulsion of possibly as many as 15 million Germans from their homes after World War II, invoking the Atlantic Charter, the Hague Conventions, and the Nuremberg Principles.

[61][non-primary source needed] The article was followed by his first book Nemesis at Potsdam (Routledge und Kegan Paul, 1977) which focused on what, if any, responsibility the British and U.S. governments had for decisions which purportedly led to the expulsions of these ethnic Germans.

[verify] Nuremberg prosecutor Ben Ferencz wrote in the American Journal of International Law that it was "a persuasive commentary on the suffering which becomes inevitable when humanitarianism is subordinated to nationalism".

[verify] The New Statesman reviewer stated: "in his well researched, closely reasoned work, de Zayas leaves little doubt that there have been few historical parallels to this record of modern mass atrocity".

The book describes some of the work of the Wehrmacht-Untersuchungsstelle, a special section of the legal department of the Oberkommando der Wehrmacht, which investigated Allied and German war crimes.

[clarification needed] The FAZ favourably reviewed the article: "Following careful study of the records, cross-checking in foreign archives and more than three hundred interviews with surviving witnesses and military judges, de Zayas arrives at the conclusion that the investigations are reliable.

[63] According to PhD candidate Robert Bard, this book "was, as [de Zayas] says, written 'to generate interest in this hitherto ignored tragedy [the German ethnic expulsions] and lead to a new respect for these forgotten victims and to more compassion and understanding for our neighbours.'

[72][clarification needed] Historians Dan Diner and Joel Golb write that the tendency of "allow[ing] the Germans to perceive themselves also as victims" is "manifest in the work of the best-selling author Alfred-Maurice de Zayas".

[75] By contrast, Andreas Hillgruber wrote in the Historische Zeitschrift: " His succinct and incisive recounting of the events are summarized in ten historical and six international law theses, that precisely because of their lucidity and balance deserve a permanent place in the historiography of the expulsions.

"[76] Gotthold Rhode wrote in the FAZ: "de Zayas lets the victims themselves tell their story, providing reports that were hitherto unknown... the book has the character of a new 'Documentation on the Expulsions' and contains descriptions of cruelties and suffering that four decades after the events boggle the mind.

(18 November 1993)[verify] Publishers Weekly: "This relatively unknown holocaust claimed more than two million lives...De Zayas... has uncovered testimony in German and American archives detailing these atrocities, adding a new chapter to the annals of human cruelty.

[verify] Twenty years later Matthias Stickler reviewed a revised edition in the Frankfurter Allgemeine Zeitung: "Es vermittelt anschaulich, gut lesbar, quellenorientiert und ohne Polemik Grundwissen zu einem nach wie vor wichtigen Thema" ("the book imparts knowledge on a still very relevant topic vividly, in straightforward language, based on reliable sources and without polemics).

"[79] De Zayas' book Nemesis at Potsdam likewise received a positive review in the Neue Zürcher Zeitung by historian Patrick Sutter.

[80] His 2011 book Völkermord als Staatsgeheimnis (Genocide as State Secret) with a substantive preface by Karl Doehring, Director of the Max Planck Institute for International Law in Heidelberg, explored the issue of who knew what when about the Holocaust.

[citation needed] German historian Martin Moll wrote that de Zayas' book ignored the fact that in other research, scholars have found convincing evidence that knowledge of murders was partial but present.

He takes issue with some of the conclusions of historians like Goldhagen, Gellately, Longerich and Bankier, and tends to agree with the analysis of Michael Marrus, Gordon Craig, Peter Hoffmann and Hans Mommsen.

But while he carefully considers the opinions of other scholars, he does not rehash what is already in the secondary literature – he takes a fresh look at the evidence, poses new questions – and proposes possible answers, avoiding guessing and extrapolation.

[88][89][90][91][92] In 2018 de Zayas sent a Memorandum to Gary W. B. Chang, Jeannette H. Castagnetti, and Members of the Judiciary for the State of Hawaii, speaking out against the continued prolonged U.S. occupation of The Hawaiian Kingdom.

[93][94] He has advocated the rights of many minorities and indigenous peoples to autonomy and self-determination in United Nations fora and before parliamentarians in the European Parliament, including the Armenians of Nagorno Karabagh, the Sahrawi population of Western Sahara, the Tamils of Sri Lanka, the Bubis of Equatorial Guinea, the Catalans of Spain, and the Igbos and Ogonis of Nigeria.

[115] On this occasion[clarification needed] De Zayas was invited as an expert by the AfD to speak on multilateralism in the 21st century, a lecture which he gave in the aula maxima of the University of Tuebingen in May 2019.

De Zayas was appointed as "Independent Expert on the promotion of a democratic and equitable international order" by the U.N. Human Rights Council at its 19th Session, which concluded on 23 March 2012.

[120][non-primary source needed] On 10 September 2014, de Zayas presented his third report on the promotion of a democratic and equitable international order to the Human Rights Council.

"[123] On 10 September 2015, he presented his fourth report to the council on the adverse human rights impacts of free trade and investment agreements on a democratic and equitable international order, and on 26 October 2015 to the General Assembly on the issue of investor state dispute settlement.

[127] In 2015, the US based magazine of global politics, Foreign Policy, consulted with the UN Independent Expert on the application of the right to self-determination in the Indonesian region of West Papua.

[140] De Zayas' report, published in August 2018, found internal overdependence on oil, poor governance and corruption had damaged the Venezuelan economy, but that "economic warfare" was a major factor in the crisis.

Alí Daniels, director of the NGO Acceso a la Justicia (Access to Justice), said that Venezuelan and Ecuadorian organizations said that, since the mission was not prepared according to independence standards of the United Nations, it could not reach valid or acceptable conclusions for the UN Human Rights Council.

[140] Nutrition expert Susana Raffalli, advisor to PROVEA and Caritas Organization of Venezuela, said de Zayas used poor evidence to support his claim, and that by then four United Nations rapporteurs had already declared that there was a "grave" situation in the country.