Donald Trump’s proposed expansion of tariffs across dozens of trading partners carries a greater risk of damaging the US economy than earlier trade disputes.Markets are treating the latest tariff plans as another chapter in a familiar story. I believe that is a mistake.The comparison many investors are making is with the first Trump-era tariff battles, particularly those aimed at China.But the scope, timing and economic backdrop are very different today.The administration is proposing tariffs of 10% to 12.5% on imports from dozens of economies, including some of America’s largest trading partners. Previous trade battles were largely concentrated on China.This proposal reaches much further into trading relationships that underpin vast sections of the US economy.The wider the net is cast, the greater the risk that the economic damage comes home.Canada and Mexico alone account for more than a quarter of total US goods trade. The European Union remains one of America’s largest export markets and a major source of machinery, industrial goods, pharmaceuticals and critical components.Many of the countries now facing tariffs are deeply integrated into US supply chains. American businesses rely on imports, machinery, industrial inputs and finished goods from these economies every day. A larger share of the costs generated by tariffs is therefore likely to land on US companies themselves.Supporters of tariffs argue they strengthen domestic industry and improve America’s bargaining position. There can be circumstances where targeted trade measures achieve strategic objectives. But broad-based tariffs carry broader consequences.Economic reality rarely respects political messaging.Businesses ultimately face three choices. They absorb higher costs and accept lower profit margins. They pass costs on to consumers through higher prices, or they attempt to restructure supply chains, often at considerable expense and disruption.In practice, most companies end up doing some combination of all three.The timing makes the risks even greater.The global economy is already dealing with multiple sources of pressure.Energy markets remain vulnerable to geopolitical tensions involving Iran and the wider Middle East. Oil prices have become increasingly sensitive to developments in the region, creating renewed inflation concerns.Inflation has proven more persistent than many policymakers expected. Businesses and households continue to face elevated costs across financing, energy, insurance and labour.Adding broad new tariffs into that environment risks creating another source of pressure for companies and consumers.Many investors are also overlooking how much has already changed since the first round of tariff disputes.Businesses have spent years restructuring supply chains, diversifying suppliers and relocating production. The easiest adjustments have already been made. Further changes become progressively more expensive, more complex and less efficient.Companies now face a far more difficult environment in which to absorb additional costs.If energy prices move higher because of conflict involving Iran while tariffs simultaneously increase the cost of imported goods and industrial inputs, many American companies face a double squeeze. Margins come under pressure at the same time as consumers become more sensitive to higher prices.This matters for investors because the implications extend well beyond individual sectors.Businesses dependent on imported inputs, manufacturing components, industrial supply chains and cross-border trade could face the greatest pressure if the measures move forward. Renewed inflation risks could also complicate the outlook for both equities and bonds.Another concern is that these tariff proposals do not exist in isolation. The administration is simultaneously pursuing investigations into excess manufacturing capacity involving several major economies, raising the possibility of additional trade restrictions in strategically important sectors.Investors should focus on the cumulative effect rather than viewing each measure independently.Markets often concentrate on which countries are being targeted. The more important question is who ultimately pays.History teaches us that a significant share of the burden frequently falls on domestic businesses and consumers.Washington is presenting these measures as a way to strengthen America’s economic position. Yet investors should examine the broader consequences carefully.Previous trade battles were more concentrated. This one is broader, arrives during a more challenging economic period and touches more of the day-to-day operations of American companies.Assuming this will play out exactly like earlier tariff disputes could prove costly.The target list is broader, the economic backdrop is less forgiving and the potential consequences for US businesses are significantly greater.For that reason, the risk of a serious self-inflicted economic wound appears higher than it was during previous trade battles.