▲本文英文版10月20日刊发在《南华早报》

虽然2024年美国总统大选最终得票情况仍存变数，但其大概率会成为美国近代历史上竞争最激烈的大选之一。此次美国大选竞争的激烈本质上反映了美国在应对“吉尔平困境”中战略选择的艰难性。虽然两党均意图通过自己的策略维护美国的霸权地位和根本利益，但不同的策略选择会产生不同的效果。预计哈里斯大多延续拜登政府的多边主义，致力于维护全球原有秩序，至少在全球大多数“非敌国”范围内继续担当公共产品提供者的角色，而特朗普奉行单边主义，希望削弱全球公共产品提供者的角色，这实际上反映出对维护霸权的方式选择和收益成本的评估存在分歧。全球公共产品的提供涉及政治、经济、军事等多个领域，但其中最为核心的是对维护美元霸权收益和成本的权衡，即如何最大化美元作为全球霸权货币所带来的收益，同时控制和分担维护这一地位的成本。

从外交军事政策看，拜登主张加强与盟友国际合作，稳固美国在国际机构中的地位，这种政策倾向于保持全球金融体系的稳定，继续支持以美元为主导的全球货币体系。而特朗普则倾向于减少美国在国际组织的参与，并将美国排除在伊朗核协议和跨太平洋伙伴关系等关键协议之外，这可能导致全球对美元的信任下降。在军事领域，虽然拜登试图通过在俄乌战争树立“维护国际正义秩序”的形象，对美元地位有正面促进，但其对制裁工具依赖的加大和在巴以问题上的双标立场在一定程度上削弱了这一努力的成效。特朗普更加坚定地执行“重回亚洲”战略，威胁要退出北约及对乌克兰的支持，这有助于美国短期内更集中精力地应对中国挑战，但从长远角度看，拜登的外交军事策略可能更有利于维护美元的国际地位，因为美元现有的霸权地位不仅来自经济实力、科技创新能力和金融发展水平，还来自政治领域的全球领导地位，军事领域的一些正式同盟关系和非正式的安全保障承诺。

从贸易和经济政策看，哈里斯预计整体上会继续拜登政府的大政方针，特朗普在其竞选纲领中承诺“维护美元世界储备货币的地位（Keep the US dollar as the world’s reserve currency）”。但从其具体经济政策导向看，从长远看，反而可能对美元地位起到削弱作用。

第一，从财政政策看，如果美国要保持债务水平可控，就需要逐步减少巨额赤字。拜登政府提交的2025年财政预案修订版提议未来十年再减少大约3万亿美元的联邦赤字，但特朗普承诺大幅减税，又不减少社会保障支出。他承诺对进口商品关税普遍增加10%，对中国进口产品征收60%或更高的关税，对避开美元的国家施加“100%的关税”。虽然在短期内这些政策可能通过增加通货膨胀风险推升美元需求，但长期看可能也会增加债务负担，使这些国家更加远离美元。

第二，虽然两党都倾向于限制非法移民，但特朗普的立场更加强硬，移民政策虽然不会直接影响美元的国际地位，但可能会通过影响美国经济增长、技术创新、国际关系和全球资本流动等方面间接削弱美元的国际地位。

第三，民主党供应链多元化战略，推动气候合作、技术创新等政策，致力于维护全球经济可持续发展，间接维护美元的国际地位，而特朗普甚至对气候变化持怀疑态度，大力支持化石燃料产业，退出巴黎气候协定，这将削弱美国在应对气候变化、绿色经济这些重大议题上的国际领导力，间接影响美元的国际地位。

理论上民主党的政策可能更有利于美元的长远地位。如何更好地维护美元的霸权地位是两党竞争中的核心议题，只是手段、策略和实际效果有所不同。哈里斯的政策倾向于通过国际合作和稳健的经济金融政策，加强美国在国际组织中的影响力，推动全球经济治理的稳定以维持全球投资者的信任，维护美元的全球主导地位。此外，其对加密货币可能采取更加严格的监管，确保比特币等数字资产不会对美元造成直接威胁。而特朗普的单边主义、政策不确定性和宽松的加密货币监管政策可能加快去中心化进程。总体上说，民主党的策略在维护美国全球领导力和管理公共品提供策略方面谋局更为深远，从长远看可能更有利于维护美元的国际地位。

但对于接近的选举和处于“吉尔平困境”的霸权国来说，这种预测具有挑战性，特别是考虑到政策的动态变化和影响链条的复杂性。比如，特朗普的关税提高了进口商品的成本，但如果美国在全球多数地区仍致力于产业链的多元化，也可能会激发出美国经济更强的增长动能，增加美国国内产品需求，从而改善美国的贸易平衡，增强美元需求；而拜登在俄乌战争、制裁方式和力度上的“精心布局”对于局势的把控能力要求极高，一旦没有掌握好分寸，也可能最终对美元地位产生削弱效果。

以下为文章英文版原文：

How Harris and Trump will seek to preserve US dollar hegemony

The “Gilpin dilemma”, an essential concept in international relations theory, stems from the analysis of hegemonic stability theory by American scholar Robert Gilpin. It illustrates the long-term challenges faced by a hegemonic power as it plays a leading role in maintaining international order. The hegemon shoulders the burden of providing global public goods at great cost.

Over time, however, the cost of sustaining the international status quo can exceed the benefits, creating a discrepancy between the hegemon’s power and its commitments. In such a situation, the hegemonic power can face the dilemma of balancing the provision of global public goods and constraints on its resources. The Gilpin dilemma also applies to the shifting influence in the international monetary system.

The 2024 US presidential election is likely to be one of the most fiercely contested in recent American history. This also fundamentally reflects the challenges the country faces in navigating its strategic choices amid the Gilpin dilemma.

While both major political parties aim to preserve US hegemony and safeguard core national interests, their divergent strategies are likely to produce different outcomes. Democratic Party nominee and US Vice-President Kamala Harris is expected to largely continue US President Joe Biden’s multilateral approach, aiming to uphold the existing global order and maintain the role of public goods provider.

In contrast, the unilateralism of former US president Donald Trump – the Republican Party’s nominee – seeks to scale back this role, highlighting a divergence in strategies on how to sustain US hegemony. The provision of global public goods spans political, economic and military dimensions, but at its core lies the calculus of maintaining the dominance of the US dollar and maximising the benefits of the dollar’s status while managing the costs of upholding this position.

From the perspective of foreign and military policy, Biden advocates strengthening international cooperation with allies and reinforcing the US position in global institutions. His aim is to preserve the stability of the global financial system and support the dollar-centric international monetary framework. In contrast, Trump favours reducing US engagement in international organisations and key agreements.

While Biden’s positioning in Russia’s invasion of Ukraine as a defender of international justice and order has provided a boost to the US dollar’s standing, his reliance on sanctions and a perceived double standard over Israel’s conduct in its war in Gaza have somewhat undermined the effectiveness of these efforts.

However, Biden’s diplomatic and military strategy is likely to be more favourable for maintaining the dollar’s global status in the long run, as political and military alliances are indispensable for the formation of today’s US dollar hegemony.

In terms of trade and economic policy, Harris is expected to broadly adhere to the major policy directions of the Biden administration while Trump’s campaign platform includes a pledge to “keep the US dollar as the world’s reserve currency”. Even so, his specific economic policy orientation could inadvertently undermine the dollar’s status.

Trump vows high tariffs on China-made cars in his first speech after assassination attempt

First, on the fiscal policy front, Biden’s revised fiscal budget proposes an additional reduction of about US$3 trillion in the federal deficit in the next 10 years. In contrast, Trump promises sweeping tax cuts without meaningful reductions to social security spending.

He also proposes a universal 10 per cent tariff on imported goods, a 60 per cent or higher tariff on imports from China and even a “100 per cent tariff” on countries moving away from using the US dollar. While these measures might temporarily boost demand for dollars by driving up inflation, they could also exacerbate the US debt burden and push more countries away from relying on the dollar.

Second, Trump’s stance on immigration is markedly tougher. While immigration policy might not directly affect the dollar’s global standing, it could indirectly undermine its position by affecting the country’s economic growth, technological innovation, international relations and global capital flows.

Third, the Biden administration’s strategy to diversify supply chains, promote climate cooperation and advance technological innovation aims to uphold sustainable global economic development, thereby indirectly supporting the dollar’s international status.

In contrast, Trump’s rejection of climate change, staunch backing of the fossil fuel industry and withdrawal from the Paris climate accord undermine US leadership on these critical issues, indirectly weakening the dollar’s standing on the global stage.

Fourth, on the subject of cryptocurrency, Harris is expected to introduce a regulatory framework for digital assets such as bitcoin. On the other hand, Trump’s looser approach to regulation of cryptocurrencies could accelerate the trend towards decentralisation.

Overall, the Democratic Party’s strategy is more forward-looking in terms of preserving US dollar hegemony and managing the strategy of public goods provision. However, for a hegemonic power facing the prospect of close elections and the Gilpin dilemma, such predictions are fraught with uncertainty, especially considering the dynamic nature of policies and the intricacies of their impact.

For instance, Trump’s tariffs might raise the cost of imported goods, but if the US remains committed to diversifying supply chains across the globe, this could also unlock stronger economic growth and improve the trade balance, thereby being beneficial to the dollar’s power.

Meanwhile, Biden’s meticulous layout of sanctions and strategic moves in Russia’s war in Ukraine requires a high degree of control over the situation. If not handled deftly, it could ultimately have a weakening effect on the dollar’s standing.