Canada and the United States have reached the point where we no longer think of each other as ‘foreign’ countries. We think of each other as friends, as peaceful and cooperative neighbors on a spacious and fruitful continent."

—President Harry S. Truman

When I served as national security advisor from 2017–2018, I took close relations between Canada and the United States for granted. I had served alongside extraordinary Canadian officers and Army units and bore witness to their professionalism and valor. There were trade tensions with Canada in that period during the renegotiation of the North American Free Trade Agreement, but Trump Administration officials worked very well with Canada’s trade representatives and Ottawa’s very capable ambassador, David MacNaughton.

I could not have imagined in 2017 that, eight years later, a well-meaning joke about an invasion would no longer be funny due to the strains in the relationship associated with President Trump’s insult calling Canada the “the 51st state” and trade actions that threaten to inflict significant damage on the economies of both nations. In the spirit of the history we don’t know, consider this paragraph I drafted for At War with Ourselves (but did not survive the final edit) about my first full day in the job as Donald Trump’s national security advisor in February 2017.

I initiated calls to counterparts including Canada’s National Security Advisor, Daniel Jean. I had not yet interviewed for the job when Prime Minister Trudeau visited the week prior and Jean was concerned about the president’s views on trade and the potential for pulling out of the North American Free Trade Agreement (NAFTA). It turns out that those concerns were well-founded. I pledged not to take our close alliance for granted and joked that, as a military historian who was well acquainted with the failed American attempts to invade Canada in 1775 and 1813, I could assure him that, regardless of how tense relations become over trade, we would not make another attempt on my watch as National Security Advisor. Gary Cohn and I would work hard to give U.S. Trade Representative Robert Lighthizer an opportunity to renegotiate NAFTA rather than withdraw. To support Lighthizer’s and the President’s agenda, we would also urge our Mexican and Canadian counterparts to make reasonable concessions.

But the consequences of tensions in the relationship are more serious than old jokes falling flat. Morning Consult reports a more than fifty point drop in Canadians’ net favorability rating toward the United States. The insults and a series of inconsistent announcements and retractions have eroded trust between the two nations. For those who have lost track of the multiple announcements of tariffs, temporary reprieves, and counter-tariffs, here is a summary:

On February 1, 2025, President Trump issued an executive order pursuant to the International Emergency Economic Powers Act imposing a 25% tariff on all Canada-origin products (except energy resources, which are instead taxed at 10%) to begin three days later on February 4.

Canada was specifically targeted for its alleged failure to curb fentanyl flows, though data shows only 43 pounds of fentanyl (0.2% of total U.S. seizures) were seized at the US-Canada border in 2024, compared to 21,100 pounds (96.6%) at the southern border. The order also mentioned the US trade deficit, the size of which the President repeatedly exaggerated, claiming it is as large as $200 billion with Canada. Rather, the U.S. trade deficit with Canada in 2024 was closer to $35.7 billion, though that is largely due to Canadian energy exports. When one factors out energy, the US has a trade surplus of $63 billion with Canada.

On February 3, 2025, just a day before the tariffs were to go into effect, the President agreed to a 30-day pause on the tariffs. As part of the agreement, Canada re-committed to a $1.3 billion border plan with nearly 10,000 frontline workers to address migration and fentanyl trafficking. Then-Prime Minister Trudeau also said Canada would appoint a "fentanyl czar" and launch a joint strike force with the U.S. to combat transnational crime. However, this plan had already been announced by Canada in December, during the Biden Administration.

On February 10, 2025, the President imposed 25% tariffs on all steel and aluminum imports, including from the largest supplier of U.S. steel, Canada. During his first administration the President asserted the tariffs were necessary to protect US national security, but that claim was found meritless by the World Trade Organization.

On March 4, 2025, the 25% tariffs took effect after the President deemed the rest of Canada’s trade renegotiation efforts insufficient. In response, Canada levied retaliatory tariffs on $20 billion of US goods and threatened tariffs on an additional $86 billion of goods within three weeks, targeting motor vehicles, steel, aircraft, beef, and pork. It also vowed to bring formal claims against the U.S. for violating the General Agreement on Tariffs and Trade and the US-Mexico-Canada Agreement (USMCA).

On March 5, 2025, pursuant to requests by Ford, GM, and Stellantis (the parent company of Jeep and Chrysler), the President delayed tariffs on auto-related goods from Canada for one month. Tariffs on imported vehicles still went into effect on April 3, prompting retaliatory 25% tariffs by Canada on U.S.-produced cars and many auto parts.

On March 6, 2025, the President canceled tariffs on 38% of Canadian goods that are being exported to the U.S. in compliance with the USMCA. The remaining 62% of Canadian products that the U.S. alleges are being exported to the U.S. in contravention of the USMCA are tariffed at rates of 10-25%.

On March 11, 2025, the Ontario Premier threatened to impose a 25% surcharge on electricity imports into the U.S. In response, the President threatened to increase tariffs on Canadian steel and aluminum to 50%. Neither of these threats came to fruition.

On March 12, 2025, Canada followed through on its aforementioned plans to further increase tariffs on U.S. products, levying a new round of tariffs on $21 billion worth of American goods.

On April 2, 2025, the President declared a new national emergency under IEEPA, citing US trade deficits, imposing a 10% baseline tariff on all imports as well as additional retaliatory tariffs on countries with which the U.S. has a trade deficit. However, this plan does not affect Canadian goods, with the March 6 plan remaining intact.

On May 3, 2025, the U.S. levied new 25% tariffs on auto parts from Canada. The White House promised to refund companies up to 3.75% of vehicle prices to partially offset tariff costs for this year.

President Trump’s and Prime Minister’s meeting on May 6, 2025 yielded little progress on tariff negotiations. Trump remained committed to imposing tariffs on Canadian goods. He nevertheless referred to USMCA as “a good deal for everybody.”

North of the border, U.S. tariffs and Trump’s disrespectful language catalyzed the Liberal Party's come-from-behind victory in last week’s Canadian federal election. New Prime Minister Mark Carney has pledged to implement counter-tariffs and defend Canada's sovereignty.

The good-natured banter with President Trump during Prime Minister Carney’s 6 March visit to the White House indicated that the relationship was on the upswing. And I am confident that, sometime in the next year, the United States, Canada, and Mexico will renegotiate the United States-Mexico-Canada Agreement (USMCA) in a way that satisfies President Trump’s concerns over fentanyl and other narcotics trafficking; unequal access to markets for certain goods (e.g. dairy and timber), and rules of origin for products or goods to address Chinese dumping and transhipment.

But most important, U.S. and Canadian leaders must rebuild trust between our nations.

The foundation for restoring trust is strong. Canada is America’s closest ally. The two nations are bound by geography, trade, and deep security cooperation. Members of the North American Treaty Organization, the United States and Canada jointly operate the North American Aerospace Defense Command, and share intelligence through the Five Eyes alliance. In 2024, the two nations, along with Finland, launched the Icebreaker Collaboration Effort as part of an increased focus on Arctic security. The United States and Canada are top trade partners with bilateral commerce topping $700 billion each year.

But there is work for Ottawa to do as well. Canada has not adequately shared defense responsibility, with Ottawa spending a paltry 1.37 percent of its GDP on its military. Increased Canadian defense spending with an emphasis on one of President Trump’s priorities, missile defense, should be one component of a positive agenda for deepening cooperation and taking advantages of opportunities. Those opportunities include improving energy security, invigorating manufacturing, enhancing supply chain resilience, countering Chinese economic aggression, ensuring cyber and infrastructure security, and expanding power generation, transmission and distribution. Practical efforts to cooperate in these areas and the benefits that will accrue to citizens north and south of the border will restore the trust eroded over the past months.

Please subscribe to Battlegrounds: Vital Perspectives on Today’s Challenges wherever you watch your videos or listen to your podcasts and look for an upcoming episode on the Canada-U.S. relationship with former director of the Canadian Intelligence Security Service David Vigneault.