Centre for International and Defence Policy (CIDP)

time to read: 9 min

Executive summary: US–Canada relations are entering an uncertain period. While NATO has so far managed to prevent the worst outcomes of U.S. retrenchment, alliance commitments remain fragile. Discussions with defence practitioners suggest that Canada–U.S. military-to-military cooperation has remained insulated from political turbulence so far. Military-to-military partnerships between US and Canada— grounded in shared training, professional norms, and operational interdependence — has provided a stabilizing anchor when high-level politics have faltered. This Policy Brief reframes Canada-U.S. defence cooperation through a sovereignty‑first lens, emphasizing how Canada can leverage resilient military-to-military ties while guarding against values friction, moral dilemmas for Canadian Armed Forces (CAF) personnel, and risks to Canada’s long‑term strategic autonomy. Furthermore, the deterioration of U.S. civil-military relations serves as a warning for Canadian policymakers about the dangers of politicization, erosion of professional norms, and blurred boundaries between civilian authority and military power. Our policy recommendations identify how Canada can fortify institutional resilience, maintain professional alignment, and protect decision‑making sovereignty in an era of instability and fraught bilateral relations with the United States.

A New Era of Canadian Strategic Vulnerability

Canada is entering a period of heightened strategic uncertainty in its defence relationship with the United States. The bilateral relationship has historically relied on high‑trust cooperation, significant defence integration, and a shared commitment to continental defence. While military‑to‑military relations have demonstrated resilience through multiple episodes of political friction, the second Trump administration has launched explicit challenges to Canada’s sovereignty, raising more serious doubts about the bilateral relationship.

The most direct and destabilizing signals have come directly from the White House. President Donald Trump has repeatedly revived rhetoric proposing Canada’s integration into the United States as the “51st state,” framing it as a quid pro quo for participation in the U.S. “Golden Dome” missile‑defence program. In a 2025 address to U.S. military leaders, Trump suggested that Canada “should become the 51st state” to access the system, a message reiterated at subsequent military gatherings that framed Canada as struggling economically and thus seeking American protection.[i] This unprecedented language goes beyond typical alliance coercion and constitutes a challenge to Canadian sovereignty, even if it is often dismissed as joke by American officials or lawmakers.[ii]  

Equally destabilizing have been Trump’s statements about taking control of Greenland, placing strains on NATO unity and Arctic cooperation. The threat to annex Greenland, which was framed as a national security imperative, resonated in Canada, which has been accelerating defence and infrastructure investments in the Arctic over the last year. These combined sovereignty challenges signal a new, more aggressive U.S. posture toward territorial influence in the Western Hemisphere.[iii] The re‑emergence of transactional American behavior has increased alliance fragility and revived concerns about U.S. reliability.[iv] Trump’s threats regarding Greenland were perceived in European capitals as undermining allied trust and respect for territorial sovereignty. At the same time, the 2025 National Security Strategy articulates an America‑first doctrine that deprioritizes traditional alliances and reduces the emphasis on collective defence.[v] For many allies, the central concern is no longer the prospect of U.S. withdrawal from NATO, but the increasingly transactional character of American security commitments - where support is treated as conditional leverage rather than as an expression of shared obligation.[vi] For Canada, this strategic shift - paired with increasingly coercive rhetoric from the U.S. - requires a fundamental reassessment of its bilateral relationship and renewed efforts to bolster its sovereignty.

Against the backdrop of political turbulence, Canada-U.S. military‑to‑military ties have remained remarkably stable. Shared exercises, interoperability frameworks, professional norms, and institutionalized mechanisms through NORAD and NATO enable predictable operational coordination even when political leaders clash. Defence practitioners consistently emphasize that such ties operate on a different logic than political relationships: they are grounded in shared professional identity, training, and mutual respect. Defence integration runs deep, particularly in air defence, maritime domain awareness, and intelligence sharing. These connections have successfully insulated bilateral cooperation during previous periods of tension. However, this insulation must not be overstated. While strong military-to-military ties can dampen volatility, they are not autonomous from civilian political environments. As demonstrated during earlier Trump-era disruptions, military leaders can become politicized or pressured. As the U.S. environment becomes more politically volatile, the protective value of military professionalism may weaken. Canada cannot and should not assume the invulnerability of these bilateral military-to-military ties.

Value Friction and Moral Dilemmas for the Canadian Armed Forces

The 2025 National Security Strategy represents a major normative shift in U.S. defence policy. It emphasizes unilateral action, prioritizes U.S. domestic political ideology over multilateral obligations, and frames alliance commitments in terms of narrow national interest rather than shared democratic values. This shift creates friction when Canadian military personnel work closely with U.S. forces whose institutional norms are being reshaped. The NSS’s strong endorsement of hemispheric dominance and its narrowed conception of U.S. obligations complicate joint operations, especially when Canadian personnel are expected to participate in missions or planning processes grounded in values Canada does not share.

Political contestation over military norms and values threatens the normative foundations of cooperation. Canada–U.S. military ties have long been grounded not only in shared interests, but in common professional norms and liberal democratic values. Recent efforts to roll back institutionalized initiatives within the U.S. Department of Defense—most notably the Women, Peace and Security (WPS) agenda—illustrate how political priorities can override established professional frameworks. In early 2025, the Trump administration dismantled WPS programs originally introduced during Trump’s first term.[vii] Under Defense Secretary Pete Hegseth, the Pentagon has also curtailed diversity, equity, and inclusion initiatives, ended official recognition of identity-based commemorations, and removed selected materials from military educational institutions.[viii] Over time, divergence in values can weaken the informal trust and shared expectations that allow military-to-military cooperation to function as a stabilizing anchor when political relations deteriorate.

Deteriorating U.S. Civil-Military Relations as a Cautionary Tale for Canada

The United States is experiencing one of the most significant breaks in healthy civil-military relations in its modern history. Trump’s earlier presidency saw the politicization of the armed forces, the blurring of the line between military loyalty and personal loyalty to the executive, and the introduction of initiatives that disrupted internal norms. During the second Trump term, these dynamics have intensified. Civilian control of the armed forces, which is rooted in mutual respect, professional norms, and constitutional boundaries, has become more precarious.

The erosion of U.S. civil–military relations during the Trump presidencies have involved traditional policy disagreements over national security issues—including Syria, Afghanistan, NATO, and relations with adversaries—that resembled earlier episodes of civil–military friction. Yet these tensions were intensified by decisions such as the ban on transgender service members and the pardoning of individuals convicted of war crimes. The politicization of senior officer promotions, including the removal or sidelining of women generals and other officers perceived as ideologically misaligned with the administration, also has profound consequences. Such actions have raised fundamental concerns within the military regarding cohesion, discipline, moral leadership, and the values underpinning the profession of arms. The result is a risk environment in which CAF personnel may face moral dilemmas in joint operations when U.S. decisions conflict with Canadian ethical standards.

Canada must heed these developments carefully. The Canadian model of civil-military relations relies on: clear delineation between political and professional roles, a non‑politicized officer promotion processes, and values‑based ethos reflecting Canadian democratic norms. U.S. degradation of these principles demonstrates how quickly civil-military norms can erode when politicized leadership pressures the military to conform ideologically. As Chivvis et al. argue, many core elements of U.S. foreign policy display significant resilience and are therefore likely to persist beyond any single administration, suggesting that current uncertainties may reflect a more structural challenge rather than a temporary disruption. The lesson is that Canada must strengthen its own institutional safeguards pre‑emptively to avoid similar vulnerabilities.[ix]

Canada should place greater emphasis on sustaining positive, routine collaboration between military and civilian personnel within defence institutions. Research on defence organizations indicates that personnel who report constructive military–civilian working relationships are more satisfied in their roles, more engaged in their work, and more committed to their organizations, while strained relationships are associated with the opposite effects.[x] These dynamics matter because morale, engagement, and institutional commitment are directly linked to organizational performance and retention.

In periods of political uncertainty or heightened external pressure, the quality of day-to-day civil-military engagement becomes particularly consequential. When institutional stress increases, weak civil–military relationships can amplify friction and undermine effectiveness; when relationships are strong, they can help absorb shocks and preserve cohesion. As such, if trade-offs emerge, maintaining functional, trust-based civil-military collaboration should be treated as a priority, supported through clear roles, consistent communication, and shared professional norms across the Defence Team.

When Military-to-Military Ties Complicate Canadian Decision‑Making

The other side of the coin is that close Canada-U.S. military integration can create vulnerabilities for Canadian sovereignty, not only politically but bureaucratically.[xi] We identify a risk in Canadian military personnel opting for U.S. operational or procurement preferences overriding Canadian strategic autonomy. The case of the F-35 is instructive here, illustrating how the Canadian military has long gravitated toward U.S. platforms.[xii] While the F‑35 remains a key capability, Canada’s consideration of a future mixed fleet (e.g., European fighters, drones, or other systems) could be met with resistance within military circles accustomed to U.S. interoperability norms. This creates risks such as reduced openness to non‑U.S. procurement options, internal bureaucratic pushback when civilian leaders pursue diversification, and potential operational penalties for diverging from U.S. equipment decisions.

The fear is that senior military leaders, who are keen to preserve seamless integration with U.S. forces, may unintentionally (or intentionally) undermine Canadian efforts to diversify capabilities. This is not sabotage in a formal sense, but it can manifest as institutional inertia, risk‑averse planning, or exaggerated claims about interoperability harm.

Conclusion and Policy Recommendations for Canada

Since Donald Trump’s re-election, a widening value gap has emerged between the United States and its Canadian and European allies. Statements by U.S. officials at the 2025 Munich Security Conference underscored this divergence, raising doubts about whether common interests can substitute for shared values as the glue holding the alliance together. These concerns are compounded by Trump’s foreign and foreign economic policy practices, which draw little distinction between allies and adversaries in advancing his “Make America Great Again” agenda. His repeated suggestions regarding the annexation of Canada - and even more pointedly Greenland - have been explicitly directed at NATO allies, further unsettling expectations of alliance solidarity.[xiii]

Canada should continue its efforts to safeguard its sovereignty through economic diversification and defence investments. Canada should also consider more specific measures to understand sovereignty through the prism of values and also pay attention to military-to-military dynamic which are assumed to be stable or invulnerable in times of political friction. First, the CAF should have updated guidelines when embedded with the United States military, so they can better respond to ethically problematic orders; have reporting mechanisms for value‑based friction; and legal protections. Second, civilian leadership should assert its authority in procurement debates by prioritizing capability diversification and assessing interoperability realistically, without allowing U.S. preferences or potentially biased military assessments to drive decisions. Third, the current context is an opportune time to invest in civil-military education across the Defence Team. This could mean expanding professional development opportunities focused on civil-military relations, reinforcing a non-politicized military culture for members of the CAF. More broadly, some sort of monitoring of U.S. civil–military developments for early warning indicators of spillovers into Canadian structures.

Ultimately, Canada’s objective must be to leverage the strength of military-to-military ties while strengthening its capacity for independent decision‑making. This requires a proactive approach - strengthening civil-military norms, investing in sovereign capabilities, and ensuring that Canadian policy remains firmly anchored in Canadian democratic values.