Trump’s High Tariffs Backfire on the North American Automotive Industry

U.S. President Donald Trump recently announced a significant increase in tariffs on imports from Canada and Mexico, with tariffs on automobiles and auto parts reaching as high as 25%. This move is said to be aimed at promoting the return of manufacturing to the U.S. while reducing the trade deficit. However, in reality, it may…


US president Donald Trump recently announced significantly raising import tariffs on Canadian and Mexican products, with a surge as high as 25% on vehicles and automotive parts. Despite being aimed at relocating American manufacturing industries and minimizing trade deficits, this could actually trigger a series of profound negative impacts.

Below is an analysis of how this policy will undermine economic cooperation and productivity in North America, particularly within the automotive industry.

Cross-border interconnected industrial chains among US, Canada, and Mexico

The North American auto industry chain forms a highly-integrated, multinational supply system that fully leverages the resource and workforce advantages of America, Canada, and Mexico. Let’s take Ford’s popular  F-150 pickup truck as an example of the massive cross-border transportation of parts and components involved in the automotive manufacturing process. This demonstrates the industrial coordination under the North American free-trade system.

Engines from America and Canada: Some engines, such as EcoBoost V6, are manufactured in plants in Michigan, US while the rest, e.g. V8, are manufactured in factories in Windsor, Canada. These products are then transported to the US for assembly.

Transmission system from America and Mexico: the 10-speed automatic transmission system for the F-150 is produced in plants in Michigan, US and Chihuahua, Mexico. Leveraging Mexico’s cost-efficient labour force, a portion of the automotive components are transported to the US for assembly.

Automotive body parts from Mexico: Metal finishing in Mexico is cost-effective and technologically mature. The completed aluminium body panels are also transported to the US for final assembly.

Electronic components from Canada and Mexico: High-tech electronic control units are sourced from Canada while labour-intensive wire harnesses are made in Mexico.

Final assembly in America: Final assembly for F-150 is conducted in factories in Dearborn, Michigan and Kansas City, Missouri.

Throughout the entire manufacturing process, parts and components are transported across borders multiple times. For instance, under special circumstances, parts and components manufactured in Mexico may be shipped to Canada for further processing. Such cross-border movements highlight the substantial degree of coordination within North American automotive industry chains.

As a result of the tax cumulative effect of this cross-border manufacturing approach, the tax burden on manufacturers is actually much higher than the Trump administration’s 25% tariff may suggest on the surface. Suppose the components are manufactured in the US at a cost of US$10. They are then delivered to Mexico for processing at an additional cost of US$10 before being returned to the US for final assembly. The tariff is US$5 at a 25% tax rate. Since the processing vale in Mexico is US$10, the tariff amounts to 50% of the processing cost in Mexico. Clearly, while the tariff rate is set at 25%, the actual cost burden across different parts of the supply chain is much heavier, especially for the labour-intensive operators in Mexico.

The above impact will not only increase the overall manufacturing cost but will also pose a challenge to the North American free-trade cooperation system. Enterprises are compelled to reconfigure their supply chain layouts, compromising overall economic efficiency.

Economies of scale hindered by high tariffs

From an economic perspective, the tariff policy will push up manufacturing costs in the two following aspects. First, direct costs: tariffs acting as an additional expense directly escalate the costs of manufacturing parts and components. For example, wire harnesses or transmission systems made in Mexico will become more expensive as a result of the tariffs. These additional costs will eventually be reflected in the sales price.

Second, indirect costs: New Trade Theory, pioneered by Paul Krugman, emphasizes that one of the advantages of international trade is that it enables companies to fully leverage economies of scale, i.e. the unit cost of production diminishes with expanding output. However, the tariff policy will lead to the automotive industry’s scale of production shrinking. As rising prices of components suppress demand, overall production will dwindle as a result. The average production costs of enterprises will shoot up as output plummets, further weakening their competitiveness.

In the aforementioned Ford Motor case, if the company cannot afford the tariffs, it will not be able to import enough low-cost components from Mexican plants, causing America’s manufacturing capacity to drop. This means that Ford will no longer be able to manufacture best-selling models like the F-150 at low costs and will, therefore, struggle to maintain its price competitiveness in the market.

Talk of American manufacturing chains returning just wishful thinking

A core objective of Trump’s tariff policy is to bring manufacturing back to the US. Unfortunately, this objective is neither practical nor economically efficient.

One formidable obstacle to restoring a large number of jobs back to the US is the inadequate labour supply. Given the historically low unemployment rate and current shortage of skilled workers for technical positions in manufacturing, any attempt to move all cross-border production chains to America will lead to manpower shortages in other industries, further driving up wages and inflation rates.

Moreover, labour costs in the US are much higher compared with countries like Mexico. Even if enterprises establish factories on American soil, they would be unable to replicate the same low-cost operations achievable in Mexico. This will severely weaken the competitiveness of American automobiles in markets worldwide.

The international division of labour in manufacturing lies in professionalism and maximizing efficiency. While Mexico specializes in the production of labour-intensive parts and components, Canada and the US focus on high value-added research and final assembly. Such a division of labour approach has equipped the North American automotive industry with global competitiveness. Nevertheless, if all production activities were concentrated in the US, companies would not only lose the advantages of economies of scale, but productivity would also sharply decline, ultimately dealing a blow to economic coordination throughout the North American region.

The lesson from cutting off one’s nose to spite one’s face

Trump’s tariff policy serves as a reminder of the Smoot-Hawley Tariff Act from the last century. Aimed at protecting American agriculture and industries, the Act was passed in 1930 and imposed high tariffs on over 20,000 imported goods. Despite its implementation, the legislature not only failed to achieve its purpose but also triggered retaliatory tariffs from other countries, significantly slashing international trade and further exacerbating the Great Depression.

The ultimate failure of the Act taught us a valuable lesson: unilaterally raising tariffs will not merely harm the domestic economy but also compromise the stability of the global economic system. Trump’s tariff policy may well repeat the same mistakes, with a heavy impact on the overall economic coordination in the North American free-trade region, especially when Canada and Mexico take punitive measures.

While Trump’s policy to levy tariffs on imports from Canada and Mexico seeks to bring manufacturing jobs back to the country, it completely underestimates the cumulative burden on producers, not to mention the production cost hikes due to direct costs and the loss of economies of scale. The writing has long been on the wall regarding the Smoot-Hawley Tariff Act: without due consideration for the complexity of the global supply chains, the tariff policy is set to inflict irreparable damage on both the domestic economy and the international trade system.

Given the advanced development of globalization today, international trade collaboration remains crucial for enhancing productivity and economic growth. The US should re-examine its trade policy to avoid making the wrong moves again and to maintain the competitiveness and resilience of the North American automotive industry by deepening regional cooperation.

Translation

特朗普高關稅反噬北美汽車產業鏈


美國總統特朗普近期宣布對加拿大和墨西哥進口商品大幅加徵關稅,汽車及零部件稅率更高達25%。此舉據稱旨在促進美國製造業回流,同時減少貿易逆差,但實際上卻可能引發一連串深遠的負面影響。

下文將聚焦汽車業,分析這一政策如何破壞北美地區的經濟合作與生產效率。

北美汽車產業鏈的生態圈


北美汽車產業鏈是一個高度整合的跨國供應系統,充分利用了美國、加拿大和墨西哥三國的資源與勞動力優勢。我們以一款流行的福特 F-150 型號輕型貨車為例,說明汽車生產過程如何涉及大量的跨境零部件運輸,從中可見北美自由貿易體系下的產業協作。

生產引擎在美國、加拿大:部分型號(如 EcoBoost V6)在美國密歇根州的工廠製造,其他(如 V8)則由加拿大溫莎(Windsor)工廠生產。這些引擎隨後被運往美國進行組裝。

傳動系統在美國、墨西哥:F-150 的 10速自動變速器由美國密歇根州和墨西哥奇瓦瓦州的工廠共同製造。墨西哥提供低成本勞動力來生產部分零部件,然後進口美國以完成裝配。

車身零件在墨西哥:墨西哥的金屬加工成本低,且技術成熟。生產鋁合金車身面板完成後,亦運至美國進行最終組裝。

電子元件在加拿大、墨西哥:高科技電子控制單元來自加拿大,而人工密集型的電線束則在墨西哥生產。

最後組裝在美國:F-150 型號在密歇根州迪爾伯恩市和密蘇里州堪薩斯城兩大工廠完成組裝。

在整個生產過程中,零部件經多次跨越國界,例如在特殊情況下,墨西哥製造的零部件可能須運往加拿大進一步加工。這些跨境流動充分體現出北美汽車產業鏈的高度協作性。

這種跨境流動的生產特性,產生稅收累積效應,以致特朗普政府徵收的表面稅率雖為25%,但實際上生產者的負擔遠高於此。假設某汽車零部件最初在美國製造,價值為10美元,之後運往墨西哥加工,提升價值至20美元,最後折返美國進行最終裝配。按照25%稅率,需支付5美元關稅,由於在墨西哥的加工價值為10美元,稅款等同墨西哥加工價值的50%。顯而易見,稅率表面上是25%,但導致供應鏈中不同環節的成本負擔實際上沉重得多,特別是對勞動密集型的墨西哥供應商。

有關影響不僅增加總生產成本,還會對北美自由貿易協作體系構成挑戰,因企業被迫重新計劃供應鏈布局,而削弱整體經濟效率。

高關稅背後的經濟成本


從經濟學的角度來看,關稅政策推升生產成本,主要分為兩大類別。一、直接成本。關稅本身作為額外支出,直接提高了生產零部件的價格。例如墨西哥生產的電線束或傳動系統因關稅而變得更昂貴,這些成本最終將反映在汽車售價上。

二、間接成本。現代貿易理論(以克魯明為首所發展出來的新貿易理論)強調,國際貿易的優點之一是有利於企業充分發揮規模經濟效應。規模經濟(economies of scale)指隨着生產規模擴大,單位生產成本則會下降。然而,關稅政策令汽車產業的總體生產規模萎縮,因為零部件價格上漲會抑制需求,總產量自然下降。當生產規模縮小,企業的平均生產成本反而上升,進一步削弱競爭力。

上述福特汽車的例子,公司可能因負擔不起關稅,而無法從墨西哥低成本工廠進口足夠零部件,形成美國工廠的生產規模減少。這就意味著,福特將無法以低成本生產出F-150 的類似暢銷型號,難以維持在市場的價格競爭力。

生產回流 談何容易


特朗普的關稅政策有一個核心目標:將生產活動「帶回美國」。可惜這一目標既不切實際,也不符合經濟效率原則。

將大量製造業崗位帶回美國,一大挑戰在於勞動力供應不足。美國目前的失業率正處於歷史低位,許多製造業的技術性崗位也面臨技能短缺問題。試圖將跨國生產鏈全部移到美國,勢必會導致其他行業人力資源短缺,進一步推高工資水平和通脹率。

此外,美國的勞動成本遠高於墨西哥等國家。即使企業在美國開設工廠,也無法實現與墨西哥相同的低成本生產,這亦勢將嚴重打擊美國汽車在國際市場的競爭力。

國際生產分工的核心在於專業化和效率最大化。墨西哥專注於勞動密集型零部件生產,而加拿大和美國則集中於高附加值的研發和最終裝配。這種分工模式使得北美汽車產業具有全球競爭力。然而,若將所有生產活動集中於美國,企業將無法享受規模經濟帶來的優勢,生產效率也將大幅下降,最終損害的是整個北美地區的經濟協作。

畫虎不成 前車之鑑


特朗普的關稅政策讓人想到上世紀的《斯姆特-霍利關稅法案》(Smoot-Hawley Tariff Act)。該法案於1930年通過,對超過兩萬種進口商品徵收高額關稅,旨在保護美國農業和工業。實施後不單未能實現預期目標,反而引發了其他國家的報復性關稅,造成國際貿易量大幅下滑,進一步加劇經濟大蕭條。

此一關稅法案以失敗告終,卻提供了一個寶貴教訓:單方面提高關稅不僅損害本國經濟,也會破壞全球經濟體系的穩定性。特朗普的關稅政策可能重蹈覆轍,特別是加拿大和墨西哥採取報復措施時,北美自由貿易區的整體協作將備受衝擊。

特朗普對加拿大和墨西哥進口商品徵收關稅的政策,雖然旨在促進美國製造業回流,但實際上完全低估對生產者的累積負擔,更因直接成本和規模經濟損失引致生產成本上漲。《斯姆特-霍利關稅法案》的警示早已寫在牆上:關稅政策若未能充分考慮全球供應鏈的複雜性,將對本國經濟以至國際貿易體系造成難以彌補的損害。

在全球化已深入發展的今天,國際貿易的協作仍是提升生產效率和經濟增長的關鍵。美國應重新審視其貿易政策,避免一錯再錯,並通過深化區域合作來保持北美汽車產業的競爭力和韌性。

趙耀華
港大經管學院經濟學榮譽副教授

(本文同時於二零二五年三月十二日載於《信報》「龍虎山下」專欄)