Is Trump putting US national security at risk with his ‘Liberation Day’ tariff blitz?

US President
Donald Trump’s decision to impose at least a 10 per cent tariff on all imports, with even higher rates for key trading partners, follows a similar approach from his first term. Back in 2018, he placed tariffs on steel and aluminium under Section 232 of the Trade Expansion Act of 1962, arguing that the US needed to reduce reliance on foreign suppliers to protect national security.

The idea behind such tariffs is that if the US depends too much on other countries—especially rivals—for important materials and goods, it could become vulnerable in times of crisis. By making imports more expensive, Trump hopes to push companies to bring factories and jobs back to the US, making the country stronger and more self-sufficient. That’s why he called this move “Liberation Day”—suggesting it will free the US from economic dependence on other nations.

However, this strategy comes with risks. Tariffs make goods more expensive for American consumers and businesses leading to higher prices and possible economic slowdowns. The 2018 steel and aluminium tariffs led to retaliation from US allies like Canada and the EU straining trade relationships. If other countries hit back against Trump’s new tariffs, the US economy could suffer even more.

While Trump sees tariffs as a way to protect US industry and national security, many experts warn they could do more harm than good. The success of this policy will depend on whether it truly strengthens the US economy or backfires making the country weaker in the long run.

Competing visions of economic security

According to an article by Jonathan E Hillman for the Council on Foreign Relations, two main views shape the relationship between economic policy and national security: the networked approach and the nationalist approach.

The networked approach recognises the risks of relying too much on foreign suppliers but sees strong alliances as a way to strengthen both economic and strategic security. Supporters of this view believe that depending on allies like Canada, Australia and the UK helps the US defence industry without requiring complete self-sufficiency.

The nationalist approach, on the other hand, argues that only domestic production can be truly reliable. This view gained support in 2018 when the Commerce Department under Trump claimed that even imports from allies could pose a security risk. The administration pushed for self-reliance breaking from past policies such as those under George W Bush, which saw a diverse and allied supply chain as an advantage.

Impact on the US defence industry

The defence industry is central to this debate since steel and aluminium are key materials for weapons manufacturing. However, research by Jeroen Klomp in PLOS One shows that US defence production has little real need for foreign steel.

Existing rules like the Buy America Act and domestic content requirements for specialty metals already ensure a strong reliance on US steel. The Department of Defence estimated that it needs only about five percent of domestic steel production contradicting claims that steel imports threaten national security.

Although tariffs were meant to protect US steelmakers from foreign competition, they also led to higher prices for domestic suppliers. These price hikes affected the defence industry, increasing costs for naval ships, fighter jets and other military equipment that rely heavily on steel and aluminium. A study by Amiti et al found that the cost of tariffs was largely passed on to domestic buyers, including the US military and its contractors.

Trade retaliation: Risks to US global standing

Beyond its domestic economic impact, these tariffs also risk damaging relationships with key allies. In the past, affected countries—including Canada and European nations—responded with their own tariffs, disrupting supply chains and altering their buying strategies.

This is especially crucial in the defence sector, where interoperability and cooperation between allies are vital. The US defence industry accounts for about 10 per cent of total US exports, so trade disputes could weaken its global standing.

If foreign governments feel alienated by US protectionism, they may turn to European or Asian defense suppliers instead. While the US remains dominant due to its technological edge, continued trade tensions could erode its leadership over time.

Risks of supply chain disruptions

Another unintended effect of the tariffs was the disruption of critical supply chains. A 2021 commerce department report admitted that Section 232 tariffs had increased costs for transformers and other essential components ironically putting national security at risk instead of protecting it. This highlighted the challenges of implementing protectionist policies without fully considering their ripple effects.

Another concern is the heavy reliance on foreign microelectronics, which are vital for infrastructure like energy grids, water systems and banking. In an interview on Federal Drive, David Schild pointed out that China’s control over printed circuit boards (PCBs) and integrated circuits raises security risks for the US.

While the Pentagon and Congress have set a 2027 deadline to stop using Chinese suppliers, reversing decades of outsourcing is difficult. The number of US PCB manufacturers has dropped from 2,200 to fewer than 145 showing the scale of the challenge.

Import penetration in Section 232 cases

The US Department of Commerce’s Section 232 investigations show that industries heavily dependent on foreign imports are more likely to be seen as national security threats. However, import reliance alone is not the only factor. Military use, supply chain risks, and domestic production capacity also influence the decision.

Industries with over 60 per cent import reliance—such as neodymium magnets (93 per cent), aluminium (90 per cent) and uranium (79 per cent)—were considered security threats. These materials are vital for defence, energy and infrastructure making local production a strategic priority. High dependence on imports raises the risk of supply chain disruptions justifying protective policies.

For industries with 40 per cent to 60 per cent import reliance, the results were mixed. Vanadium (40 per cent) was classified as a security threat because it is crucial for steel used in defence, while Integrated Circuit Ceramic Packages (60 per cent) and ferroalloys (61 per cent) were not. This suggests that if domestic alternatives exist and supply chains are stable, security concerns may be lower even with moderate import reliance.

Industries with less than 40 per cent import reliance were generally not considered security threats. For example, steel (34 per cent), gears (18 per cent) and iron ore (14 per cent) had strong domestic production, reducing concerns about foreign supply risks.

The findings show that defence-related materials face stricter scrutiny than consumer or industrial goods. While high import dependence increases the chance of being labelled a security risk, domestic production strength and strategic importance also matter. These factors shape US trade policies with industries vital to national security receiving stronger protection to reduce foreign reliance.

Policy alternatives

The Section 232 tariffs on steel and aluminium highlight the ongoing debate between economic protectionism and national security. The Trump administration defended these tariffs as a move toward economic self-reliance, but evidence shows they also created unintended problems such as higher costs for the defence sector, strained relations with allies and supply chain disruptions.

Instead of broad tariffs, a more balanced approach—combining domestic investment with strategic international partnerships—would likely provide stronger long-term security. As global competition grows, policymakers must carefully evaluate economic policies to ensure they truly protect national security rather than unintentionally weakening it.