As global risks such as climate change, pandemics, cyber threats, and financial contagion cross borders with increasing intensity, there is growing demand for mechanisms that enable transnational accountability. However, existing legal instruments remain fragmented, with limited enforceability or jurisdictional reach. This question seeks expert perspectives on the current legal foundations—both hard and soft law—that could support the attribution, enforcement, and governance of cross-border risk responsibilities. Key areas include state liability, international environmental law, extraterritorial obligations, principles of common but differentiated responsibilities, and emerging norms under climate litigation and multilateral treaty frameworks.