由於提供數位經濟服務的跨國公司不須在市場國建立恆久據點，導致利潤來源地政府無法適用傳統的常設機構原則進行課稅。面對此項國際稅收分配的挑戰，經濟暨合作發展組織（Organisation for Economic Cooperation and Development, OECD）在2013年公告「防止稅基侵蝕與利潤移轉計畫」 （BEPS），試圖建立一致的課稅替代方案。然而，部分國家後續卻自行開徵數位服務稅，美國川普政府對這些國家威脅使用301條款並發起關稅報復，直到2021年美國拜登政府支..

Host countries cannot tax digital multinational corporations (MNCs) based on the traditional permanent establishment principle because digital services are intangible. To address this challenge, the Organisation for Economic Cooperation and Development (OECD) initiated the “Base Erosion and Profit Shifting” (BEPS) multilateral regime in 2013. Nonetheless, several host countries hunting for revenue unilaterally adopted digital service taxes, and the US Trump administration responded with Section 301 tariff retaliation from 2019 t..

在一個以美國為首的後冷戰單極國際體系中，次級強權與美國之間的動態性權力安排，將直接影響單及體系是否得以續存。傳統國際關係理論主張「權力平衡」是維持國際社會與區域安全的穩定要素，但該理論針對的是強權間為維持軍事戰略利益，所採取以軍事力量作為手段的平衡關係，對於後冷戰時期美國與其他次級強權的互動，似乎缺乏解釋的效力。在這些次級強權當中，歐洲聯盟扮演一個非常特殊的角色。歐洲與美國同享重要的文化與宗教價值，但在具戰略意義的議題上，兩者的歧見卻益形明顯。歐盟在重大國際議題上與美國的背道而馳，已形成..

In a U.S.-dominated post-Cold War unipolar international system, the possible power shifts between the second-tier great powers and the Americans, such as a systemic balance, will have great impacts on the existence and endurance of the current international system. According to the Realist theses, “balance of power” is a stabilizing factor that contributes to international security and regional stability as the great powers endeavor to prevent concentration of capabilities in one or a few nations through the process of distribu..