According to the Compendium of the Social Doctrine of the Church, war is the failure of peace. This is, in my opinion, an excellent way to describe war; especially if we adopt the Augustinian idea that the peace between peoples and nation states is best understood as a "tranquility of order." More than just the absence of armed hostilities, tranquility of order means peace with (at least a tolerable amount of) social justice.

This is why modern popes have reminded us, as Paul VI did, that if we want peace we should work for justice. Blessed John Paul II, in recognizing the important link between integral human development and social justice, stated it this way: "Another name for peace is development" (Centesimus Annus, 52, marking the 100th anniversary of Rerum Novarum, Pope Leo XIII’s encyclical on capital and labor). And this year, in his World Day for Peace Message, Pope Francis built on Benedict XVI’s teaching in Caritas in Veritate (Charity in Truth), stressing the importance of genuine fraternity between peoples and nations as an absolute necessity to building a more just and peaceful world.

For Francis, the loss of genuine fraternity leads to the scourge of war: "For this reason, I appeal forcefully to all those who sow violence and death by force of arms: In the person you today see simply as an enemy to be beaten, discover, rather, your brother or sister and hold back your hand! Give up the way of arms and go out to meet the other in dialogue, pardon and reconciliation, in order to rebuild justice, trust and hope around you! ‘From this standpoint, it is clear that, for the world’s peoples, armed conflicts are always a deliberate negation of international harmony and create profound divisions and deep wounds which require many years to heal. Wars are a concrete refusal to pursue the great economic and social goals that the international community has set itself.’"

But if war will not achieve "the great economic and social goals" of the international community, what can be done, short of war, to influence those nations or groups or leaders on the world stage who stubbornly refuse to pursue peace with justice?

In the Compendium, one response is legitimate defense of the innocent and new forms of international cooperation and intervention. Another "measure against those who threaten peace" is sanctions, including economic sanctions: "Sanctions, in the forms prescribed by the contemporary international order, seek to correct the behavior of the government of a country that violates the rules of peaceful and ordered international coexistence or that practices serious forms of oppression with regard to its population. The purpose of these sanctions must be clearly defined, and the measures adopted must from time to time be objectively evaluated by the competent bodies of the international community as to their effectiveness and their real impact on the civilian population. The true objective of such measures is to open the way to negotiation and dialogue. Sanctions must never be used as a means for the direct punishment of an entire population: It is not licit that entire populations, and above all their most vulnerable members, be made to suffer because of such sanctions. Economic sanctions in particular are an instrument to be used with great discernment and must be subjected to strict legal and ethical criteria. An economic embargo must be of limited duration and cannot be justified when the resulting effects are indiscriminate" (507).

In other words, sanctions, like any social policy, must be judged by the objective moral standards of justice. Foundational to a robust notion of justice is the dignity of every human person and our special obligation to those most in need of our care and protection.

Sanctions should only be applied after other forms of negotiation and diplomacy have failed to end the unjust practice or policy. They must be both limited and targeted against those responsible for the injustice (i.e., political, military and social leaders). They cannot be indiscriminately imposed on entire populations.

This last point is a modern application of the just-war principles dealing with siege and blockades. These principles date back to some of the earliest codes for proper conduct between belligerents.

For example, Michael Walzer, in his classic Just and Unjust Wars, cites the "Talmudic law of sieges" used by both Jewish and Christian sources for centuries: "When siege is laid to a city for the purpose of capture, it may not be surrounded on all four sides, but only on three, in order to give an opportunity for escape to those who would flee to save their lives." This principle means that a military commander cannot turn the civilian population of a city into a legitimate target for bombardment or starvation just by laying siege to their city.

Non-combatants remain non-combatants unless they actively take up arms against their enemy. By similar reasoning, economic sanctions cannot be applied against an entire population in a way that would indiscriminately deprive them of the basic needs for sustaining life: food, water, shelter, medicines, etc.

Three modern examples of economic sanctions might help illustrate these points. First is the international boycott of so-called "blood diamonds." This was the concerted effort to ban the importation, use or trade in diamonds from those areas of the world where they were being used as currency by rival warlords to fuel genocidal conflicts in various parts of Africa, most notably in the Congo region, Liberia and Sierra Leone. The ban met with some degree of success and aided in bringing some temporary stability to those regions.

A second example involves the U.S. sanctions on Iraq after the end of the first Gulf War in 1991 up until the invasion of Iraq in 2003. These economic sanctions were imposed ostensibly to keep the Iraqi regime from developing weapons of mass destruction. However, they were so extensive and so punitive, as Joy Gordon of Fairfield University has shown in her book Invisible War: The United States and the Iraq Sanctions, as to do massive harm on a totally indiscriminant level. Gordon writes: "For thirteen years, the United States unilaterally prevented Iraq from importing nearly everything related to electricity, telecommunications and transportation, blocked much of what was needed for agriculture and housing construction, and even prohibited some equipment and material necessary for health care and food preparation."

Numerous independent reports have detailed the massive humanitarian disaster caused by these sanctions, with at least 200,000 deaths (some estimate a much higher figure) attributed to the embargo. This is a clear example of an unjust application of economic sanctions.

A third example relates to the current sanctions against Iran to impede development of nuclear weapons. The sanctions have to do with export restrictions, technology transfers, arms importation, missile parts and travel and currency restrictions, especially for scientific, military and government leaders, etc.

While these sanctions seem both targeted and limited, the effect on the entire Iranian economy cannot be discounted. In addition, although medicines are not part of the embargo, the financial restrictions have led to many shortages in Iran. These side effects should be monitored and humanitarian efforts allowed to alleviate innocent suffering.

However, the goal of sanctions, as the Compendium states, is to lead to negotiations. These sanctions motivated the Iranian leaders in late 2013 to re-engage in meaningful dialogue with the so-called "P5+1" group of nations. A temporary, tentative agreement was reached last month. Time will tell if significant long-term breakthroughs can be achieved, but the situation looks brighter at the start of 2014 than it has in decades.

Economic sanctions are one tool, albeit a limited one, available to world leaders to achieve "the great economic and social goals" associated with a more just and peaceful world. Often, however, these types of sanctions are way too draconian or punitive in intent, too broad in their effects, too harmful to the poor and innocent to be justified.

All this being said, the "tranquility of order" is usually better served by the judicious and targeted use of economic sanctions than the brutality of war. An even better way is to work for genuine economic and social development and true justice, so that neither sanctions nor war is necessary.

Since we all desire peace, let us work for social justice for all.

Msgr. Stuart Swetland,

a 1981 graduate of the U.S. Naval Academy,

holds the Archbishop Harry Flynn Chair of Christian ethics

at Mount St. Mary’s University in Emmitsburg, Md.

He served six years as a line officer in the U.S. Navy.