Democratic Peace Theory: An Appropriate Guide to Foreign Policy?

The idea behind democratic peace theory (DPT) has evolved since its inception in 1795 and today is ‘the fundamental postulate of liberal foreign policy’ and one of the defining characteristics of Western civilisation (Doyle in Smith 2008: p. 49). However, when it comes to Western states applying this ideology to non-Western states, the consequences have usually been dire. After defining the theory and shedding some light on its evolution over the years, this paper will then explore the case study of the United States. The U.S. has arguably the longest history of applying DPT to foreign policy and therefore provides an ideal case by which to assess the appropriateness of such an application. Despite great potential, however, in conclusion the export of DPT has proven it defective in three critical areas – areas that must be addressed before it could ever be considered a panacea. This paper will then confront those three issues that need to be dealt with before other states continue or start applying DPT to their foreign policies.


In 1795, Immanuel Kant described what he deemed were the necessary prerequisites for a peaceful world. In the second section of this work, Perpetual Peace, Kant wrote that ‘the first definitive article of perpetual peace’ is that ‘the civil constitution of each state . . . be republican’ (p. 9). Kant believed that the foundational assumptions of republican government were essential to a world without war. These three fundamental assumptions were that man has a right to freedom, man has a right to be subject to a common law under which every other man is subject, and lastly, all men are equal citizens. But the most compelling argument lies in the nature of the government itself. While an autocratic ruler can declare war and reap the benefits of domination without having to worry about the opinion of his countrymen who have no voice, a republican ruler is subject to his countrymen who inevitably bear the brunt of the burden that a declaration of war implies. Therefore, since a republican ruler is theoretically only the voice of the people – the people whose blood, sweat and tears must finance any war – he will only declare war if it is seen as a matter of survival. The second and final prerequisites were ‘a principled respect for the nondiscriminatory rights all human beings can rightfully claim’ and ‘social and economic interdependence’ (Doyle in Smith 2008: p. 61). But it was the first ‘definitive article’ – this idea that a state with a republican form of government is much less likely to go to war – that laid the foundation for what is today referred to as DPT.

It was not until the second half of the twentieth century however, that the idea behind DPT started to become more popular and fall under the scrutiny of quantitative research. The first such article appeared in 1964, ‘Elective Governments – A Force for Peace’, in which the author, Dean Babst, concluded that his ‘study suggests that the existence of independent nations with elective governments greatly increases the chances for the maintenance of peace’ (p. 14). In the 1970’s, the discipline of Foreign Policy Analysis was starting on a ‘second wave’ of empirical research. In the tradition of James N. Rosenau, foreign policy analysts began to search for a connection between a state’s internal characteristics and its foreign policy. The most popular question seemed to be along the lines of ‘Are there characteristics of a state that make it more likely to go to war? And if so, what are those characteristics?’ Yet:

Statistical manipulation of aggregate data . . . was unable to uncover any lawlike generalizations on this score . . . However . . . one notable exception burst forth upon the scene: democratic peace theory (Hudson in Smith 2008: p. 23).

Eventually, articles started appearing in academic journals making such claims as ‘democracy, in and of itself, has a consistent and robust negative effect on the likelihood of conflict’ (Maoz & Russett 1993: p. 624).

A few decades later, one bold claim effectively thrust DPT into the spotlight and, as some could argue, reduced the theory ad absurdum. In 1992, Francis Fukuyama’s The End of History and the Last Man was published, in which Fukuyama claimed that liberal democracy is the ultimate form of political ideological evolution: once every state becomes a liberal democracy (which seemed to be the trend when this work was written), these states would no longer go to war (based on the assumption of DPT). And with no more wars, history, as the world’s record of conflict and violence, would essentially be over.


No country has applied democratic peace theory to its foreign policy as consistently as the United States. In the words of Henry Kissinger:

Secure between two great oceans, [the United States] rejected the concept of the balance of power, convinced that it was either able to stand apart from the quarrels of other nations or that it could bring about universal peace by insisting on the implementation of its own values of democracy and self-determination (2002: p. 25).

Hence, when evaluating DPT as a guide to policy, the U.S. presents an ideal case study: with few exceptions, each presidential administration since President Woodrow Wilson has used DPT as the basis of its justification for foreign intervention, particularly war.

According to Omar G. Encarnación, professor of politics at Bard College, President Woodrow Wilson was the first to embrace DPT as the foundation of U.S. grand strategy. In 1917, Wilson supported his request of Congress for a declaration of war against Germany, which he called a ‘natural foe to liberty’, with the immortal words ‘the world must be made safe for democracy’. President Wilson’s belief in the virtues of freedom was so strong that he saw the spread of liberal democracy not just as a worthy cause that the U.S. should passively promote, but also as a reason in itself to go to war. President Franklin D. Roosevelt followed in Wilson’s footsteps. Speaking at the Wilson Center, Charles Maier, professor of history at Harvard University, stated that one of ‘two tenets . . . central to Wilson’s and FDR’s political agendas’ was ‘the belief that a peaceful stance in world politics depended on the [democratic] nature of regimes’ (2008). This tenet became an implicit assumption for almost every succeeding U.S. president as each in turn vowed, in so many words, to defend democracy, not just at home but abroad.

After World War II, the United States came to see the existence of the Soviet Union as a threat to liberty itself: President ‘Truman perceived the emerging struggle . . . as a contest between good and evil’ (Kissinger 1994: p. 447). The resulting Truman Doctrine, which said ‘the policy of the United States [is] to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures’, was an explicit statement that the defence of democracy was indeed U.S. foreign policy (Truman 1963: p. 178). The practical application of the Truman Doctrine that emerged was the containment policy, which was the basis for the two major instances of U.S. foreign intervention during the Cold War: Korea and Vietnam. President Truman ‘[justified] the American role in Korea in the familiar Wilsonian terms of freedom versus dictatorship, good versus evil’ (Kissinger 1994: p. 477). In his 1949 inaugural address, Truman said the U.S.

will strengthen freedom-loving nations against the dangers of aggression . . . in addition, we will provide military advice and equipment to free nations which will cooperate with us in the maintenance of peace and security (Truman 1964: pp. 112-114).

And fearing a domino effect, ‘by 1950, the Truman Administration had decided that the security of the free world required Indochina to be kept out of communist hands’ (Kissinger 1994: p. 625). The tragedy that became the Vietnam War lasted for six successive presidential administrations, each of which saw the war as a fight for freedom itself. It was not until later administrations that the role DPT assumptions played in the formation of the U.S. foreign policy agenda would be made explicit.

President Bill Clinton’s faith in DPT led to U.S. involvement in several overseas exploits in the Balkans, not to mention the aptly named Operation Uphold Democracy in Haiti. Perhaps Clinton’s 1994-1995 National Security Strategy best sums up his position towards basing U.S. foreign policy on DPT:

Our goals of enhancing our security, bolstering our economic prosperity and promoting democracy are mutually supportive. Secure nations are more likely to support free trade and maintain democratic structures. Free market nations with growing economies and strong and open trade ties are more likely to feel secure and to work toward freedom. And democratic states are less likely to threaten our interests and more likely to cooperate with the United States to meet security threats and promote free trade and sustainable development (cited by Grinberg 2005).

And yet, President George W. Bush, in his second inaugural address, was the most succinct and explicit: ‘The best hope for peace in our world is the expansion of freedom in all the world’ (2005: A24). Though the rationale behind invading both Afghanistan and Iraq could be argued in terms of national interest and power politics, the decision to bear the cost for trying to implement democracy and run free elections in these states can only be reasoned on the assumptions of DPT.


After almost a century of applied democratic peace theory, perhaps it is time to ask whether DPT really is an appropriate guide to foreign policy. During World War I and World War II, appropriateness was, for the most part, never called into question. Though President Wilson and FDR were both believers in DPT as mentioned above, they were also successful in convincing the U.S. public that entry into WWI and WWII was in the national interest.

It was not until the Korean War that a gap started to appear between the long-term goal of world peace (i.e. the “moral” goal) and more immediate national interests. This gap translated into both strategic and philosophical dilemmas. One such strategic dilemma came in the form of ‘limited war’. According to Kissinger,

‘though Truman had powerful geopolitical arguments in favor of intervention in Korea, he appealed to the American people on the basis of their core values, and described intervention as a defense of universal principle rather than of the American national interest’ (1994: p. 477).

And ‘once the issue had been raised as being beyond power politics, it became extraordinarily difficult to define practical war aims’ (Kissinger 1994: p. 477). Indeed, the U.S. struggled greatly with the concept of ‘limited war’ that came about as a result of the containment policy:

In a limited war, if military and political goals are not synchronized from the very beginning, there is always a danger of doing either too much or too little. Doing too much and allowing the military element to predominate erodes the dividing line to all-out war and tempts the adversary to raise the stakes. Doing too little and allowing the diplomatic side to dominate risks submerging the purpose of the war in negotiating tactics and a proclivity to settle for a stalemate. In Korea, America fell into both of these traps (Kissinger 1994: p. 480).

Though the Korean War held many lessons about strategy, the Vietnam War would prove to be a tragic turning point, not just strategically, but philosophically as well.

According to Kissinger, up until Vietnam, ‘the test of America’s policies was not so much feasibility – which was taken for granted – as worthiness’ (1994: p. 622). By not looking at the feasibility of its crusade, the U.S. significantly overextended itself so that even if the country had learned its strategic lesson from Korea, it could do nothing about it. Kissinger aptly described the U.S. commitment in Vietnam as ‘large enough to get America entangled, not significant enough to prove decisive’ (1994: p. 626). The long, messy Vietnam War sparked so much emotion as well as divisive and bitter rhetoric both in the U.S. and abroad that logical debate on the strategy and philosophy behind it were nearly impossible. Strategically, the liberal foreign policy agenda of the U.S. proved to be so ambiguous that poorly defined war aims were inescapable and so general that overextension was unavoidable. Philosophically, the U.S. made the mistake of allowing a disconnect between the idealistic moral crusade of promoting democracy for the ultimate end of a peaceful international society and the realistic near-term end of protecting national interests. This disconnect proved fatal for domestic unity and morale. It was during this time that realist scholar Hans Morgenthau said that U.S. liberal foreign policy ‘ran the risk of multiplying enemies and expanding commitments beyond the country’s means’ (Wohlforth in Smith 2008: p. 42).

While Clinton’s use of U.S. force in the Balkans and Haiti might have sparked anew criticism domestically about the role of the U.S. abroad, the overall strategic success of these operations did not produce a significant debate about the philosophy behind aggressively promoting democracy abroad. It was not until the U.S. military ran up against unforeseen obstacles in Iraq in 2003 that a scholarly debate was again ignited about using democracy promotion as U.S. grand strategy.

So, is democratic peace theory a panacea? It could be. But there are three major obstacles to overcome:

1.) A philosophical gap between the near-term goals related to national interest and the long-term goal of international stability.

2.) The strategic problems that naturally result from the aforementioned political dilemma (e.g. limited war) and an overly ambitious foreign policy (e.g.     overextension).

3.) The concept of democracy itself.

Writing in the Washington Post shortly after being named President George W. Bush’s Secretary of State, Condoleezza Rice claimed:

Like the ambitious policies of Truman and Reagan, our statecraft will succeed not simply because it is optimistic and idealistic but also because it is premised on sound strategic logic (2005).

By arguing that the greatest threats to international security are currently coming from weak and failed states, former Secretary Rice effectively made a case for the idea that actively promoting democracy abroad is a means that could affect both the long-term end of a peaceful international society as well as those more immediate national interests. By doing this, Rice started to close that philosophical gap between the long-term goal of world peace and the more immediate national interest.

Though some of the philosophical problems with a liberal foreign policy based on the assumptions of DPT have the potential to be solved, there still exist severe strategic problems. However, in the words of Kissinger:

That there are limits to the applicability of a foreign policy principle does not, of course, invalidate its relevance in particular cases. It does, however, require . . .  [an understanding of] the relationship between moral principle and day-to-day foreign policy (2002: p. 258).

Hence, Kissinger’s solution was to take more careful account of ‘historical conditions’ and context when applying moral principles (2002: p. 258). Michael W. Doyle, professor of International Affairs, Law, and Political Science at Columbia University, suggests that liberal foreign policy become more defensive in nature:

The strategy should first preserve – protecting the community and managing and mitigating the normal tensions among liberal market economies – and then expand . . . by three methods: it should begin with ‘inspiration’, focus on ‘instigation’, and, thereby, call upon ‘intervention’ only when necessary (Doyle in Smith 2008: p. 64).

Finally, the problem with the concept of democracy itself. States need to come to the realisation that democracy is not ‘one size fits all’; that democracy is not an exportable commodity that can simply be shipped as is to other societies; that democracy cannot be engineered by drafting a government on paper. Democracy is an idea that has to grow organically. And if this idea is to grow in different types of soil, from the rocky ground of South Asia to the sands of the Maghreb, it has to find root in the norms and values of the native society. In other words, a ground-up approach.

Thus in conclusion, a liberal foreign policy based on the assumption of DPT – that liberal democracies will be less likely to go to war with each other – does have flaws and weaknesses. However, peaceful, international democratic regimes such as the European Union exist and provide a shining example of what democratic peace theory promises: a society that solves its problems without recourse to war and violence. Therefore even though fixing these flaws and strengthening these weaknesses may be difficult, time-consuming and painful, the promise of peace is surely worth the effort.


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Written by: Jennifer Jackson
Written at: University of Kent
Written for: Professor John Groom
Date written: May 2011


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