This REA illustrates that, over the past decade, national digital identity systems have evolved into mechanisms through which digital sovereignty is both asserted and reimagined as a fluid, strategic political project — with states continually negotiate between centralising risk and control, and models that centre citizens to protect privacy and security within borderless digital infrastructures. This REA highlights that the ambiguity of digital sovereignty, and its various interpretations, are shaping the development of national digital identity systems in three key ways.

First, findings show that infrastructure and technology choices—from centralised, federated and user-centric, to SSI management models—have evolved to reflect a state's digital sovereignty ambitions, with contemporary systems varying widely. Where centralised, federated and user-centric models emphasise state control as they wrestle with citizen privacy, emerging SSI models that look to decentralise identity remain experimental and unproven. These findings show that although digital sovereignty is not bound to a specific model, it is continuously negotiated through practical trade-offs between state control, citizen autonomy, and infrastructural independence—with hybrid approaches becoming increasingly common to balance these tensions.

Second, although legal and regulatory frameworks establish a basis for asserting digital sovereignty, alone they are insufficient to accommodate dynamic technological change. Collaborative governance and participatory design models have emerged as administrative processes to help policymakers navigate this complexity, but there is limited empirical evidence of their effectiveness. These findings suggest that there is unlikely to be a one-size-fits-all approach to governing digital identity systems as a mechanism for digital sovereignty—especially given the diverse interpretations of digital sovereignty across contexts.

Third, the implementation and adoption of national digital identity systems reveals that digital sovereignty ambitions often lack considerations of the socio-technological dimensions required for them to succeed. This REA finds that while trust is an essential element of these systems, approaches that lack contextual appropriateness and sensitivity to citizens' knowledge, experiences, and abilities are likely to undermine any effort to implement them.

This REA concludes that policymakers are at a crossroads: caught between the urgency to "solve digital identity" (Stokkink & Pouwelse, 2018) and the complex trade-offs that digital sovereignty demands. As the literature finds, digital identity remains unsolved. For policymakers to move forward, they must continue to develop hybrid approaches to technology and infrastructure that balance state control and infrastructural independence, experiment with new governance processes that encourage collaboration, and make a decisive shift toward citizen-centred approaches that get closer to the lived experiences of citizens.