In coping with climate change, governments – both at national and local levels – increasingly have to deal with radical change. This term refers to situations characterized by (i) a multidimensional concurrence of different types of changes (political, socio-economic, cultural, organizational, environmental), (ii) drastic (non-path dependent) alterations of public planning and spending priorities and (iii) a generalized perception of crisis and insecurity among stakeholders and civil societies. The climate-related determinants of radical change are in principle well known by now, even though their concrete scope and impacts are still quite difficult to predict. They include issues of adaptation, mitigation and integrated ecosystem management. However, research on the political capability of states to actually manage those changes has been rather limited so far. In particular, a basic coin of adaptability, sustainability and resilience, the legitimacy of political orders, has been largely neglected by the scientific debate. Legitimacy rests on the acknowledgment that a political order exists “rightfully” and that its exponents (the “government”) act in the common interest. It gives states the authority to formulate and implement binding decisions and helps them to mobilize societal resources to meet common challenges. Every political order designed to last in time engages in the strategic procurement of legitimacy, but there are different modalities of legitimation and individual political orders are characterized by a specific (but by no means inalterable) mix of modalities. The proposed paper uses an analytical approach which identifies six modalities of legitimation. The concept will be applied to the political management of climate-related radical change. The main objective is to assess the capability of existing political orders to manage change from a common interest perspective, and the options to strengthen democratic legitimacy in the context of climate change.