從兩次世界大戰至今，國際政治結構與秩序發生幾次重大的轉變。集體安全制度的形成、戰爭形態的改變、以及全球化與區域化發展所帶來新的問題與威脅等，使傳統「中立」制度與觀念面臨存廢的挑戰。另一方面，實踐上，有關「中立」概念的主張與應用卻始終存在。有鑒於此，本文擬從國際政治發展的不同階段，以宏觀的角度來探討「中立」概念的源起以及法律與政策面的發展與轉變，嘗試對「中立」概念在現代國際秩序中的角色與作用進行理論和實踐的觀察與分析。

從法律層面來看，傳統戰時中立的國際法制度並未被淘汰，但在集體安全制度形成以後，其功能受到很大的限制，同時規範內容更新發展的腳步， 似乎也趕不上國際環境變化的需求。在政治層面的發展上，國際社會成員對於中立的性質與作用，已由傳統的消極轉為積極的思維。過去嚴守中立的國家普遍意識到，中立作為外交政策的原則，只是保障國家安全與利益的一個選項;在現今的國際環境中，個別國家的利益與國際社會共同的價值與利益密不可分。政治上完全自我孤立的中立政策，反而可能不利於外交關係的和諧，也無益於國際合作與和平。

整體而言，「中立」概念在歷經幾個世紀的發展以後，至今仍有其存在的價值。實踐上也證明，「中立」作為法律制度或者政策性的概念或原則， 或多或少仍保有傳統中立概念的基本屬性。至於「中立」未來的重要性，甚至存廢，與國際政治包括集體安全制度的發展，息息相關。這是在一個國家在詮釋或應用中立概念的政策思考上，不應忽略的面向。

Since the two World Wars, the structure and order of international politics have undergone considerable changes. In particular, the creation of the collective security system, new forms of warfare and new problems and threats emerging from globalization and regionalization, challenge the value of “neutrality” in the new international environment. But in practice, contrary to stated facts, states continue to make use of the concept under international law or in international politics. Thus, this article tries to provide an overview of the origin of “neutrality” and its dual developments into both an international normative institution and a policy tool in international politics.

From the legal perspective, the international law of neutrality has not been abolished, although its function is greatly limited under United Nations’ collective security. Its existing normative contents also seem to lag behind new needs of the changing international environment. On the political level, the general perception toward the nature and function of neutrality has changed from traditionally more passive to positive. Even those countries that upheld “absolute neutrality” in the past now concede that “neutrality” is no longer the only policy option for guaranteeing national interest and security. In fact, the interest of an individual state is closely interwoven with the collective value and interest of the international community. A neutrality policy based on complete self-isolation is neither conducive to promoting good relations with other states nor to international cooperation and peace.

This article concludes that whether as an international law institution or a policy tool, “neutrality” will continue to exist for some time to come. However, its future relevance will depend on the development of international politics, including the collective security system.