U.S. Diplomacy Plays Critical Role in Irregular Warfare
Dr. John A. Pennell, Irregular Warfare Center – Editor-in-Chief of PRISM: The Journal of Complex Operations (Contractor)
Introduction
Diplomacy in irregular warfare (IW) is not a supporting act; it is one of the main ways the United States competes for power and legitimacy below the threshold of conventional war. That claim matters even more now because the ongoing Russia-Ukraine war has shown that contests over legitimacy, sanctions, coalition management, information, logistics, and economic resilience are not ancillary to war; they are central to it. The same is true in a wider environment of confrontation involving Iran and other revisionist actors, where influence, coercion, and political signaling often occur well before or alongside open combat.
Under the U.S. Department of War’s (DoW) DoD Instruction 3000.07, “Irregular Warfare,” effective September 29, 2025, IW is treated as a persistent form of warfare and competition in which state and non-state actors use indirect, asymmetric, and often non-attributable means in pursuit of strategic effect. The instruction is especially relevant here because it emphasizes that military force alone is often insufficient and that successful IW requires integration with other US government (USG) agencies, allies, partners, and international organizations.
While definitions of diplomacy abound, in this article, diplomacy is defined as the management of international relations through representation, negotiation, persuasion, and coordination, consistent with the U.S. State Department’s (DoS) description of its role as the lead U.S. foreign affairs agency. Beyond diplomacy, statecraft is the broader orchestration of diplomatic, informational, military, and economic (DIME) instruments in support of national objectives. That distinction matters because diplomacy is one instrument of statecraft, but in IW it is often the instrument that integrates the others. Joseph Nye’s concept of soft power, the ability to shape the preferences of others through attraction rather than coercion or payment, and his concept of smart power, the strategic combination of hard and soft power tools, are useful here because irregular competition is fundamentally a struggle over legitimacy, perception, and political will as much as over force itself. Based on on-the-ground diplomatic experiences across the globe, this article argues that U.S. ambassadors and their embassy country teams are central to how Washington wages IW against hybrid threats.
IW as Statecraft
In the last decade-plus, U.S. thinking about IW has evolved from a narrow “small wars” frame centered on counterinsurgency (COIN) and special operations toward a broader understanding of politically driven competition for legitimacy, access, influence, and will. The September 2025 update of DoD Instruction 3000.07 makes that shift explicit by treating IW as an enduring method by which DoW employs military capabilities as part of a larger whole-of-government approach in strategic competition. Contemporary analysis of the instruction has similarly argued that the Pentagon’s new guidance is significant precisely because it institutionalizes IW as a core competency and ties it more clearly to competition with adversaries such as Russia, China, Iran, and their partners.
This broader conception of IW blends nontraditional force with political action, information operations, and economic pressure rather than treating them as separate domains. That logic was already visible in the IW Annex to the then 2020 National Defense Strategy (NDS), which framed IW as an approach for competing below the threshold of armed conflict while shaping the environment for deterrence and warfighting when necessary. It also appears in other analysis, which stresses that the central object of IW is political legitimacy and strategic influence, not merely tactical disruption.
As Carl von Clausewitz argued in On War, war is a continuation of policy by other means. The significance of that formulation is not rhetorical; it means that warfare, including IW, is fundamentally political in purpose even when it is military in method. If that is true, diplomacy cannot be an afterthought. It is the arena where coalitions are built, narratives shaped, sanctions negotiated, access maintained, and escalation managed. Yet, many IW debates still begin with raid cycles, proxies, and covert capabilities, and only later ask how an ambassador, a sanctions package, or a public messaging campaign fits the larger political design. In practice, that sequence is off.
Ambassadors at the Center of IW
As noted, in the United States, DoS is the lead foreign affairs agency and the principal manager of America’s relationships overseas. U.S. ambassadors, as chiefs of mission (COMs), are the President’s personal representatives and are charged with directing, coordinating, and supervising executive-branch employees in their countries of assignment, with specific statutory and operational exceptions. That authority is reflected in the Foreign Affairs Manual (FAM), which states that the COM has “full responsibility for the direction, coordination, and supervision of all Government executive branch employees in that country,” except for employees under a U.S. Combatant Commander (COCOM) and a limited number of others. These authorities, including the COM’s interagency role, are summarized elsewhere.
In practical terms, ambassadors and country teams are the default integrators of diplomacy, security cooperation, public communication, and economic statecraft overseas. In Kyiv, for example, after Russia’s 2014 annexation of Crimea, its support of proxies in Donbas, and its extensive IW campaign across Ukraine, that reality was inescapable. The U.S. mission had to align sanctions and security assistance with allies, respond to intensifying Russian disinformation and subversion, and support a newly elected Ukrainian regime, all while maintaining a coherent political message. U.S. material support to Ukraine, in addition to its partnership with Ukraine as evidenced by the U.S.-Ukraine Charter on Strategic Partnership, though still evolving, illustrates how the DIME lines of effort (LOEs) were linked rather than separate.
Three patterns became clear. First, nearly every “irregular” LOE, from training Ukrainian units to exposing Russian propaganda narratives, depended on diplomatic access and political cover. Second, sanctions and financial tools had to be synchronized with embassy political and public messaging, because poorly sequenced moves from Washington could undercut local efforts. Third, coordination with Ukrainian, EU, and NATO partners was itself a near full-time diplomatic task, particularly if allies differed over the type and extent of costs to impose on Moscow. Those dynamics show why the embassy is often the real operational hub of IW in the field, even when the most visible activities appear tied to the military domain.
A Framework: Four Aspects of Diplomacy in IW
Those experiences suggest a practical framework for thinking about diplomacy in IW. Diplomacy in IW is not a single activity but a set of overlapping practices that can be grouped into four aspects: political diplomacy, military diplomacy, public diplomacy, and economic diplomacy.
Political diplomacy is the traditional domain of foreign ministries and ambassadors: negotiating agreements, aligning partners, managing crises, and shaping the political environment in which all other tools are used. In an irregular context, those functions do not disappear; they become more decisive. In Ukraine, for example, political diplomacy meant more than issuing joint communiqués. Embassy work underpinned strategic partnership frameworks and the political assurances that made sustained security assistance viable on both sides of the relationship. It also meant constant work with allies to keep sanctions aligned despite differing domestic politics, threat perceptions, and energy dependencies, a challenge reflected in DoS’ own explanation of sanctions implementation as a diplomatic process involving international coordination and partner engagement.
Military diplomacy is often underappreciated in discussions of IW. It includes security cooperation, arms sales, joint exercises, advisory deployments, defense dialogues, and training programs that shape partner capabilities, perceptions, and posture over time. In IW, these activities are never purely technical. They send political signals to partners, adversaries, and domestic audiences alike. In Georgia, for example, military diplomacy was most effective when nested in a broader interagency strategy rather than as a parallel stream. In Tbilisi, the U.S. embassy had to navigate “frozen” conflicts in Russian-occupied Abkhazia and South Ossetia, domestic political polarization, and a regional environment in which Russian influence remained strong even when local governments sought deeper Western ties. U.S. security cooperation and exercise participation were watched closely in Moscow. Each decision to expand training, launch a new program, or pause a visible activity had implications for escalation, deterrence, and domestic political narratives about the West. The country team therefore had to weigh military benefits against diplomatic risks, ensuring that security cooperation did not inadvertently feed narratives of Western encirclement or regime-change conspiracy that Russia could exploit.
If IW is about legitimacy and narratives, public diplomacy sits at the heart of the contest. NATO and European work on strategic communications and hybrid threats has repeatedly stressed that information and perception are operational domains, not merely public-relations concerns. In practice, that reality reshapes diplomacy itself. In Ukraine, Russian disinformation campaigns long sought to portray Ukraine as corrupt, divided, and controlled by foreign interests. Those narratives targeted not only Ukrainians but also Western publics to erode support for sanctions on Russia and aid to Ukraine. The U.S. mission’s public diplomacy response therefore had to combine ambassadorial statements, social media, public events, and support for independent journalism and fact-checking with broader interagency campaigns to expose Russian lies and publicize evidence of Russian involvement in the Donbas and, later, broader atrocities. What mattered was not any single message but the sustained shaping of the information environment.
Economic diplomacy is arguably the most visible and potent diplomatic tool in contemporary IW. Sanctions, export controls, investment screening, financial pressure, and targeted economic assistance can erode an adversary’s capacity to wage war, limit its ability to reward benefactors, and shape its strategic choices. But these tools do not operate in a vacuum. They are negotiated, explained, adapted, and politically sequenced through diplomacy.
The Russia-Ukraine war turned economic statecraft into a central front of irregular competition. U.S. and allied sanctions after 2014, and especially after the full-scale invasion in 2022, aimed to degrade Russia’s military-industrial base, constrain access to advanced technology and capital, and signal long-term costs for aggression. In practice, that required major diplomatic effort. U.S. embassies across Europe and beyond had to explain sanctions packages to host governments and local business communities, coordinate with EU and G7 partners, identify loopholes, and manage blowback when restrictions imposed costs on friendly economies.
Effective economic diplomacy in IW has at least three requirements. First, it must be embedded in a broader political strategy that clarifies what behavior economic pressure is meant to change, or whether the measures are primarily punitive, deterrent, or degradative. Second, it must be implemented through embassy-led coalitions that understand local economic structures and can target measures with precision. Third, it must be connected to positive alternatives such as investment, trade access, and targeted assistance so that partners are not simply asked to absorb economic pain on behalf of U.S. strategic objectives. This latter point deserves more attention than it often receives. Economic resilience is not only about denying adversaries revenue; it is also about building credible alternatives. Recent analysis of agriculture as an emerging front in hybrid warfare underscores that food systems, agricultural inputs, logistics, and related commercial channels can function as instruments of leverage and resilience, not just as economic background conditions). In that sense, financing agricultural commodities, protecting critical supply chains, and supporting food-system resilience can be part of an IW toolkit rather than a separate development concern.
The Caucasus and Central Asia provide an especially revealing case. As the United States and European partners try to restrict Russia’s ability to reroute sanctioned goods through third countries, embassies in Kazakhstan and Uzbekistan must walk a tightrope. They must reduce sanctions evasion while recognizing that these economies depend heavily on trade with Russia and that overt pressure can push partners toward Moscow or Beijing. Transport infrastructure is part of that same competition. The much-discussed Middle Corridor has become strategically important because it offers Central Asian and Caucasus states alternatives to Russian transit routes, but recent analysis argues that governance obstacles, infrastructure bottlenecks, climate pressures, and geopolitical risk may sharply limit how scalable the corridor becomes in practice. At the same time, other reporting shows that participating states have accelerated corridor planning, digitalization, and container growth in 2026, underscoring that logistics routes are now central objects of geopolitical competition rather than neutral commercial infrastructure.
What Diplomats Bring to IW
First, diplomats bring a “relational” understanding of power. They see how small moves—an official statement, a sanctions designation, a military exercise, a grant to a local NGO, or a transport initiative—reverberate through elite networks, media narratives, business communities, and public opinion. That perspective is essential for designing IW campaigns that do not win tactical exchanges while losing strategic legitimacy.
Second, embassies embody the interagency in the field. Country teams bring together political officers, defense attachés, economic and commercial officers, public affairs professionals, law enforcement representatives, and intelligence personnel. When an ambassador is empowered and attentive to irregular threats, that team can integrate tools in ways that Washington alone rarely can. COM authority exists for precisely this reason.
Third, diplomats often have the “clearest” feel for escalation risk. Local incidents can quickly acquire symbolic importance. A mis-phrased public statement, a sanctions designation that doesn’t consider host-nation (HN) realities, or a poorly timed training mission can feed an adversary’s “malign” narratives. Ambassadors, their country teams, and HN staff are often first to detect these shifts, and their assessments should shape IW planning rather than merely react to it.
In other words, IW against a sophisticated adversary is fundamentally about managing complex political ecosystems. That is the core competence of diplomacy.
Making Diplomacy Central to IW
If the United States and its allies and partners want to compete effectively in IW, they must put diplomacy closer to the center of IW thinking and practice. That requires at least four practical steps.
- First, joint campaign planning between embassies and military commands should be more formally institutionalized. While COMs and COCOMs do not perform the same function, they must be treated and empowered as genuine partners in shaping politically coherent plans. Shared concepts, regular planning routines, and mechanisms for resolving disputes over risk and escalation are essential if the United States wants to compete effectively below the threshold of war.
- Second, embed IW and hybrid-threat literacy in professional development. Training in the basics of the DIME, information operations, strategic communications, and partner resilience should be core preparation for diplomats rather than niche electives. The logic of DoD Instruction 3000.07 already assumes integrated campaigning; civilian training should catch up to that reality.
- Third, treat economic diplomacy as integral to IW rather than as a separate policy silo. Sanctions packages, economic assistance, and resilience initiatives should be designed with embassy input and partner consultation from the start, and they should be calibrated with public messaging and security cooperation from the outset. The ongoing war in Ukraine has shown that economic measures can be strategically decisive but are most effective when they are politically sequenced and diplomatically sustained.
- Fourth, use European institutions and regional initiatives as platforms for conceptual alignment and more balanced burden-sharing. NATO Centers of Excellence (COEs), EU-NATO cooperation on hybrid threats, and issue-specific partnerships around sanctions enforcement, strategic communications, and logistics resilience can help bridge the “vocabulary gap” between military IW practitioners and civilians who may prefer the use of terms (e.g., hybrid threats, resilience, or statecraft) other than IW but also drive greater European and NATO leadership and resourcing in these areas. Functional convergence—and a more equitable distribution of effort across NATO and EU partners—matters more than semantic purity.
In conclusion, IW is decided as much in embassies, foreign ministries, sanctions coordination cells, and multilateral institutions as on conventional battlefields. The United States and its allies and partners can either organize for that reality or allow adversaries to exploit any seams among the DIME instruments. Field experience demonstrates that when COMs lead fully integrated teams and campaigns, diplomacy becomes not just the backdrop to IW but one of its most effective instruments.
Dr. John A. Pennell is a contractor with the Irregular Warfare Center (IWC), serving as the Editor-in-Chief of PRISM: The Journal of Complex Operations. He’s also a former U.S. Senior Foreign Service Officer (Minister-Counselor) with more than 20 years of field experience in every region of the world including in combat and hybrid warfare zones.
