Luther on Wars of Necessity

I discuss Luther’s “wars of necessity” in my book Christianity in an Age of Terrorism, which CPH asked me to write after the 9/11 attacks but which, if you don’t mind my saying so, still holds up surprisingly well today.

To explain, I’m going to quote myself–don’t you hate it when writers do that?–by sharing some lecture notes based on passages from that book:

Luther warned about relying too much on the justness of one’s cause when waging war. Trusting in one’s own righteousness is deadly in the spiritual realm, and it can be dangerous in the earthly realm as well. The just-war theory was an integral part of medieval moral philosophy. Luther believed that this approach to morality, under which actions can be justified or condemned by checking off criteria, neglects the radical power of sin, which taints even our good works, and encourages a naive “works-righteousness” that obscures the Gospel. Luther approaches war from a different angle, condemning with a pacifist’s zeal any kind of religious war, while, in light of his doctrine of the two kingdoms and his doctrine of vocation, seeing warfare in light of God’s judgment and grace and recognizing the legitimacy of what he called “wars of necessity.”

War of Necessity

The main function of earthly government, according to Romans 13, is to protect its subjects and to punish evil. In a sinful world, this often entails using force and “bearing the sword.” Just as an earthly ruler has the right to use force within his borders, Luther believed that he has the right to use force outside his borders, when this is necessary for the biblical mandate to protect his people.

The only legitimate war, therefore, according to Luther, is a defensive war. Paul Althaus summarizes Luther’s teachings about war:

Implicit in what Luther says is that he recognizes only a defensive war which is forced upon us by an aggressor. War is right only when it is “our only miserable way of defending ourselves.” Luther knows that most wars are waged for quite different reason: selfish motives of princes and lords, lust for the property and possessions of others, desire for glory, the feeling that our honor has been insulted, wrath, and the desire for revenge. However, a Christian prince is forbidden to wage war for such reasons. The one and only purpose of a war must be to protect his subjects against attack. In this sense the decision to go to war and the decisions about how war is to be waged must be quite “simple.” [The Ethics of Martin Luther, p. 137]

Thus, according to Luther, “Whoever starts a war is in the wrong.” [Whether Soldiers Too Can Be Saved, LW: 46:117]

But those who have been attacked are engaged in what Luther called a “war of necessity.” This kind of war is in contrast to those launched intentionally and deliberately, which he described as being from the devil. A war of necessity, though, is a “human accident, in which we can expect God’s help” [ibid., 46:120].  The prince must wage this necessary war “joyfully and with a good conscience” [ibid.], decisively, energetically, and with the confidence that he is within God’s will .

Luther actually goes beyond just-war theory, with even stricter principles against what can justify warfare. His point, though, is not to just set up legalistic criteria. Rather, he wants to prevent both rulers and their subjects from trusting in the justice of their cause, as if this will ensure success. As Althaus summarizes:

Anyone who trusts in his own cause and his own power is foolhardy. As seriously as Luther admonishes a prince to do his duty in a specific instance and to use his weapons to protect his subjects, and as strongly as he emphasizes the prince’s responsibility for his country, he in no way creates the expectation that the prince whose “cause is just” will win. Luther says to the prince: Because your whole country is threatened, you must take the risk and see whether God wants to help you. Luther speaks of risk because no one knows how the conflict will end. Even the fact that one has been attacked and has good reason to defend himself does not guarantee his success. It is of no use to emphasize the justice of one’s cause, for this, like all pride, stubbornness, and security, is an abomination to God. We ought not to rely on the justice of our cause, only on God’s grace and mercy. [Ethics of Martin Luther, p. 140]

In war, as in every other facet of life, we remain under the cross and we are utterly dependent on the grace of God.

So how can we apply the criterion of “necessity” to modern wars?  Opinions will differ, of course, as to who started the war and who were merely defending themselves.  And we must remember what Milton said in response to the rhetoric of Satan in Paradise Lost, in which the fallen angel insists that his rebellion and his warfare against the human race are necessary.  The narrator dismisses that claim in four words:  “Necessity, the tyrant’s plea” (IV. 393-394).  The point being that tyrants are always invoking “necessity” to justify their atrocities.  But let’s try applying Luther’s concept:

World War I–not a necessity

World War II–necessity

Korean War–possibly a necessity

Vietnam–probably not a necessity

The War on Terrorism–necessity

Iraq War–not a necessity

How about the current war between Russia and Ukraine?  Was Russia’s invasion of Ukraine a “war of necessity”? No.  By Luther’s standards, a war to acquire another nation’s territory is always wrong.  Is Ukraine’s war against Russia a “war of necessity”? Yes.  By Luther’s standards, defensive wars are always necessary.

Providing aid, of course, is a different proposition than actually waging a war.  Should the United States send troops into Ukraine (which I don’t think anyone is advocating)?  Not a necessity.  Should the U.S. send aid to a nation being attacked?  Possibly, if fending off that invasion would deter other invasions.

The extent of that help would not seem to be addressed by Luther’s analysis, nor would the details of ending such a conflict.  I would think, though, that ending the bloody conflict is a “necessity,” no matter whose cause is just.

Illustration:  Gustavus Adolphus in Action (probably at Lützen) [the Lutheran king of Sweden in the Thirty Year’s War] via Picryl, public domain.