Resilience Assurance for Critical Systems: Lessons from the 2025 Interlock Whole-of-State Infrastructure and Public Safety Summit

Critical infrastructure systems, spanning domains including water, electricity, transportation, and communications, are the centerpiece of modern quality of life, national and international security. Traditionally, reliability has been used as a primary measurand of system health and functionality, facilitating the development of robust methods for evaluating systems. However, novel threat vectors, increasing system complexity, and deeper cross-domain interconnections reinforce a growing interest in resilience, rather than reliability, as the principal measurement of system safety. The recent "Interlock: Whole-of-State Infrastructure and Public Safety Summit," held in Denver, Colorado in September 2025, brought together experts from across infrastructure domains to discuss the achievement of resilience. This work presents the lessons learned from those discussions regarding the apparent roadblocks to achieving system resilience, and outlines potential strategies to implementing system resilience approaches. Infrastructure systems across the globe are becoming more complex, more tightly coupled, and subject to expanding natural and anthropogenic threats. While it is increasingly clear that resilience is a critical system characteristic, gaps in resilience theory and application have hindered the development of resilience-centered approaches to systems engineering. This work provides the foundations to overcome some of these barriers, and suggests continued areas of research for establishing resilience engineering as a coherent science.

Keywords: Resiliency, Systems Engineering, Critical Infrastructure.