President Donald Trump recently imposed 50 percent tariffs on approximately $20 billion worth of goods imported annually from Canada, using Section 338 of the Tariff Act of 1930 as the legal foundation. These tariffs apply to a range of products including hockey sticks and alcohol. However, the phrase "up to 50 percent" does not mean that the president can impose such high tariffs freely or in response to any perceived unfairness. Section 338 was designed to give the president a tool to retaliate against foreign countries that discriminated against U.S. imports in tariff and customs matters, not to impose penalties for any arbitrary reason. This context is informed by a recent decision by the Federal Circuit Court in the case HMTX Industries v. U.S., where the court examined the expansion of tariffs on Chinese goods under Section 301 of the Trade Act of 1974. The court ruled that the U.S. Trade Representative's authority was not limitless and that any modified tariffs had to be directly related to the original goal of addressing the specific unfair trade practices under investigation. The court emphasized that tariffs could not be applied for any reason or at any level that was not "appropriate" to achieve the original objective. These principles may be significant in the case of Section 338. In July, Trump claimed that Canadian measures involving automobiles, dairy, and alcoholic beverages discriminated against American exports of cars, cheese, and alcohol. However, the tariffs also aim to increase domestic production and employment in the U.S. and potentially pressure Canada to remove the discrimination. These goals vary in nature—compensating for lost export markets is corrective, protecting domestic producers from foreign competition is protectionist, and using economic pressure to change policies is coercive. The term "offset," as defined in Section 338, means "to counterbalance or to compensate for something else," which limits the president to imposing tariffs that compensate for the burden Canada's discrimination places on U.S. companies. According to White House estimates, the alleged lost exports amount to $5.6 billion for autos and $582 million for alcohol, significantly less than the $20 billion in goods subject to the 50 percent tariffs. Additionally, cars and car parts are not on the list of products subject to tariffs, raising questions about how these tariffs are supposed to protect American car producers from Canadian competition. The HMTX case suggests that courts should be cautious about allowing the imposition of tariffs for any amount, on any product, for any reason the president chooses. The court did not grant the U.S. Trade Representative unlimited power to impose tariffs on China once an actionable practice was found. If Canada adopted a measure costing American exporters $500 million annually, the president could not respond with $10 billion in tariffs on unrelated Canadian products solely to pressure Ottawa. The statutory maximum indicates how far the president can go if the facts support a maximum tariff, but it does not dictate how far the president should go in any particular case. Congress instructed the president to offset the burden or disadvantage of a particular type of discriminatory action, which requires a clear connection between the injury and the remedy. Trump’s decision to go directly to the statutory maximum raises questions about whether the 50 percent tariff is necessary to offset a demonstrated Canadian disadvantage or if it represents the amount of pressure chosen to pursue a trade war. If 50 percent represents what is necessary to offset a demonstrated Canadian disadvantage, Trump has a statutory argument. If, instead, it simply represents the amount of pressure Trump chose to pursue the newest of his many trade wars, then something fundamentally different has happened.