冷戰結束後，分離主義運動再度興起，許多國家面臨族群分裂危機。在政治制度的設計上，英國、西班牙均被歸類為單一制國家。然而，英國內部卻存在三個不同自治程度的「行政特區」；西班牙全國分為十七個自治區，也並非每個自治區的權力相同，因而改變了單一制國家中央與地方間的權力分配關係。中央與地方間的權力關係，並非是一種「零和遊戲」，在權力不對等的情況下，如何相互尊重彼此的立場，經由協商、談判化解爭議，並從權力和利益分配的現實角度，達到一定程度的「權力平衡」，是現代化國家必須思考的問題。本文藉由蘇格蘭與加泰隆尼亞獨立公投的個案研究，探究單一制國家採用「權力下放」和「聯邦化安排」原則，在「中央集權」與「地方分權」兩個對立的體系和概念下，分析並解釋其制度變遷的過程。

After the end of the cold war, separatist movements emerged again, and many countries faced the crisis of ethnic disintegration. In the design of the political system, the United Kingdom. and Spain are classified as unitary states. However, there are three different degrees of autonomy in administrative regions within the UK. Spain is divided into 17 autonomous regions, but not every autonomous region has the same power, thus changing the unitary state power distribution between central and local governments. The power relationship between central and local is not a zero-sum game. In the case of unequal powers, how to respect each other's position, resolve disputes through negotiation and negotiation, and achieve a certain degree of balance of power from the realistic angle of the distribution of power and benefit, is a question that the modernized country must ponder. Through the case studies of Scottish and Catalonia independent referendum, this paper explores the principle of "decentralization" and "federalism arrangement" in unitary states, and analyzes and explains the process of institutional change under the two opposing systems and concepts of centralization and decentralization.