The introduction to a research-based book co-authored by O'Malley in 2022 states: What a nation chooses to remember or forget speaks to its contemporary priorities and sense of identity...understanding how this process works enables us to better imagine a future with a different, or wider set of priorities[25]: p.10  The authors claim that the narrative about how the modern nation of New Zealand is shaped by history remains contested and the ways in which the New Zealand Wars, which took place between 1843 and 1872, are remembered or forgotten, reflect "how memory and silence about this difficult past permeates people's lives in the present".

[37] The data from the research had shown a significant number of complaints against the students' petition, which according to O'Malley indicated many held a view of the country's history that was "steeped in political nostalgia and idealism...[a]... mythical version where James Cook is a hero and New Zealand had the greatest race relations in the world ", and it was challenging for them when confronted with an alternate reality.

[42] Research by O'Malley in 2013 that examines the events leading up to the invasion of Waikato by British Imperial Troops authorised by the governor George Grey, finds there is no valid justification for this pre-emptive action, noting in particular the lack of definitive evidence that there was to be an attack on Auckland.

It was said that the book explained how increased numbers of immigrants from Britain and Ireland had created high demand for Māori land in the mid-1850s, and despite attempts by local iwi to resolve issues, there were still violent interventions by the government troops.

[44] The media article noted O'Malley had previously said it is unfortunate that most of the New Zealand populace are dismissive of the Wars because "being honest about historical civil conflicts is essential to reconciliation and healing in communities and the nation".

[46] In the introduction to the report, O'Malley clarifies that the project was to assist councillors in considering the historical evidence that supported a possible name change of the city of Hamilton and the renaming of specific streets.

[47]: p.3  This involved developing portraits of those who had streets named after them, including former New Zealand governor and politician Sir George Grey, Prussian-born soldier and artist Gustavus Ferdinand von Tempsky, and former Native Affairs Minister John Bryce.

Hamilton Mayor Paula Southgate acknowledged that the process began with O'Malley's report [which had] "identified three street names as being particularly egregious to Māori", and she hoped people in the city would have an open mind toward the changes.

Tureiti Moxon said it was "a great occasion as Māori history was becoming a bigger part of the city's fabric", noting that some of the street names were a reminder of a colonial past which had caused suffering and trauma [and] "precipitated the theft of a million acres of land from this region".

The book has been described as the combination of an "incredibly rich set of sources – extracts from diaries, memoirs, letters, official documents and newspaper reports – with meticulous scholarship and a perfect editorial balance", often showing the dilemmas Māori leadership had in deciding their approach to the Wars, the details behind the confiscation of land by the Crown and vivid details of "some of the atrocities committed during the wars such as the killing of settler families at Matawhero or the deliberate burning down of a whare at Rangiaowhia while several Māori were inside".

"[55] The point has been made by O'Malley that "any discussion of contemporary Māori poverty that fails to acknowledge the long history of invasion, dispossession and confiscation is missing a vital part of the story".

[2]: p.3  Interviewed by Jesse Mulligan on RNZ in September 2024, O'Malley said the Wars were significant because they defined the kind of country New Zealand was at the time and "what it aspired to become", noting victory by the Crown and scant regard for the Treaty of Waitangi has resulted in many issues around acknowledging rangatiratanga for Māori that are still under debate.

[56] His position on the way forward is to "learn the details of some of those terrible incidents they are difficult to erase from the memory...[and]...understanding, mutual respect and dialogue will bring us together not tear us apart.

[62] Beyond the Imperial Frontier: The Context for Colonial New Zealand (2014),[63][64] is a series of essays collated by O'Malley that explore the ways Māori and Pākehā interracted in the years before 1840 when there was a degree of cooperation, to the decades after the signing of the Treaty of Waitangi which are seen as being more competitive.

One reviewer said the essays "explore some of the legal, social, judicial, military and political instruments employed by the Crown to extend its areas of influence, setting those against Māori strategies developed in response".

[62] According to O'Malley these varied greatly in different parts of the country, and although there was a risk to the balance of power due to the numerical superiority of Māori and their increased access to firearms, appreciation of mutual needs by both parties meant there were incentives to maintain peace.

[67] In evaluating Māori responses to threats of losing land or becoming totally subservient to European culture during the nineteenth century, O'Malley argues in an article in Ethnohistory Journal, that colonisation had left Māori with "disease, depopulation, land loss, and the threat of being overwhelmed by a flood of incoming European migrants, particularly after formal British annexation following the signing of the Treaty of Waitangi in 1840", and that their challenge was to survive in the post-Waitangi era without being "entirely subsumed by the new colonial order".

[2]: p.4 In 1852 New Zealand got a new constitution from Britain that allowed for a parliament to be set up, but as O'Malley notes the entitlement to vote was based on individual property holdings issued by the Crown, and as most Māori were joint holders of tribal land, they were not enfranchised.

O'Malley notes unofficial runanga were often called in to assist with "collective decision-making...[effectively meaning]...an intended instrument of English law was thus in some respects remoulded for customary Māori purposes".

[70]: p.7  In this paper however, O'Malley concludes that Grey's plan received little support and argues that, particularly in Northland where the scheme was fully implemented, Maori retained concerns about the possible intrusion of the government into areas over which rangatira had authority and control".

[71]: p.176  He examines a challenge to this approach by revisionists, including Alan Ward, that began in the 1950s and resulted in "established orthodoxy" which held that the Court did not further Māori interests and this has been a key tenet of the Waitangi Tribunal set up in 1975 to consider historical land claims.

[71]: p.177  O'Malley then explores what he calls "neo-revisionist" approaches that conclude the court was not as bad as portrayed by earlier historians, citing Richard Boast who wrote in 2008 [that]..."just because the Native Lands Act came to have consequences that were widely perceived as disastrous...it does not prove that this was intended from the beginning".

In a report for the Tūhoe-Crown Settlement, an agreement ratified by the people of Ngāi Tūhoe on 4 June 2013,[77] he writes that the tribe - who had never signed the Treaty of Waitangi - made demands for autonomy after the Crown assumed sovereignty of their lands.

When this was unsuccessful the police raided Kenana's settlement at Maungapohatu in 2016, arresting him on disputed charges of sly-grogging and killing his son, leading O'Malley to conclude: "by 1921, Tūhoe autonomy was all but finished.

[9] It presented the historical events around the land confiscations that lead to a breakdown in relations between Māori and the Crown, and concluded that the people of Te Rohe Potae became caught up in the Waikato War and despite claims at the time that they had been warned in a proclamation by Governor Grey of an impending invasion by British troops, had no "opportunity to comply with the demands set out in the proclamation" which were in effect an ultimatum, and as a result were unable to protect "their own lives and lands.

These included many "conflicting accounts...[of]...several highly controversial incidents", the "chaotic, disorganised, confusing and poorly documented process" of land confiscations and the lack of a "single coherent Crown voice.

"[82]: 10–12  The report concluded:Responses to the raupatu on the part of Te Rohe Potae hapu and iwi, along with their wider kin, were remarkably diverse, encompassing a range of different tactics and strategies, though all underpinned by a shared sense of loss.

[81] One reviewer says that while there has been research about the role of the Waitangi Tribunal [with]..."the capacity to enrich New Zealanders' knowledge of their nation's history and deepen their understanding of race relations today...most of that work has remained under the public radar but [O'Malley] draws on several facets of that historiography to place some key events under a sharper light.

[89]: p.86  O'Malley and Kidman suggest [that] "for many Pākehā New Zealanders an emphasis on historical aggrievances, and even on ethnic or racial differences cut across an imagined nation identity that was both harmonious and homogenous".

[96] Category convenor Nicholas Reid said the book "tells us of the past but is relevant to the present, when public debate feeds New Zealanders’ hunger to know how our country was formed...[and is]...nuanced in its balance of both Māori and Pakeha voices and it respects the attitudes and assumptions of people who lived in an era different from our own.