Justifiable Invasion

Is Invasion ever Justifiable?

When, if ever, does one country have an acceptable reason to invade another? This is a hard question, but I will attempt to answer it. There are two dimensions to the question: a legal justification and a moral justification.

Types of War

Let us start by looking at the types of war. War can be defined in various ways.

• Defensive war where one country defends itself from invasion, e.g. Ukraine. Of course, Russia did not consider it a defensive war until Ukraine captured parts of Russia.
• Pre-emptive war. While under imminent threat of attack, a country strikes first. In many cases, this is an excuse for gaining the upper hand before a potential threat is realised. Egypt was attacked by Israel in 1967 in a pre-emptive strike, which resulted in the Six-Day War. Israel considered Egypt was about to strike, so it struck first.
• Preventive war. Attacking a country because it is a potential threat is a preventive war. Examples include Germany attacking Russia in World War II, as it saw Russia, which was neutral, as too big to stop in the future. The 2003 Iraq war was a preventive war.
• Humanitarian war. Going to war to stop violence and genocide. The most recent example is the war in Yugoslavia, where Serbs, Bosnians, and Croatians were being slaughtered.

War is generally when two or more countries engage in attacks on one another. One participant might think of the war as one type, while the other thinks of it as another.

A Just War

To attack another country means attacking three groups. The government of the country, the military tasked with defending the country, and the citizens. If it is a humanitarian intervention, are you attacking only the government and the military? Inevitably not. Civilians are always harmed as collateral damage. If the reason is humanitarian, some of the humans you set out to save will inevitably be killed. Can this be justified?

Looking through historical literature, five criteria for a just war were identified.

• Just cause
• Legitimate authority
• Right intention
• Proportionality
• Last resort

Legal Justification

Under modern International law, the central player in justification is the United Nations; however, the UN model is flawed. The Security Council has to justify the war, and it includes all the power players representing opposing political philosophies: the United States, the United Kingdom, France, Russia, and China. Only one has to object, and the motion cannot be passed. On rare occasions, there has been consensus. In 1950, they approved Korea; in 1991, the Gulf War; in 2011, the Libyan Intervention; and in 1992, Somalia.

The Security Council did not approve the 2003 invasion of Iraq by the United States and allies, Russia’s invasion of Ukraine in 2022, or the 1999 NATO intervention in Serbia during the Kosovo crisis. Other wars, such as the Gaza war, never reached the council.

There is another path under the UN Self-Defence (Article 51). A country may use force if it is responding to an armed attack. This was the path the UK followed in response to an Argentine invasion of the Falklands in 1982. Ukraine has used this path to justify defending against Russia since 2022.

To answer the legal question: under international law, unless the UN Security Council approves the conflict or the country is defending itself under Article 51, it is illegal to engage in war.

Morality

Moving on to the question of morality, it becomes more complex. We talked about the different types of war, and each needs to be examined from a moral perspective.

Defensive wars are usually moral. If a state is attacked, an invasion may be required of the aggressor’s country to repel the aggression. For example, for Ukraine, striking inside Russia seems perfectly acceptable given that they are repelling an aggressor. It becomes a little more opaque when you look at the case of the US invasion of Afghanistan after 9/11. Did the Taliban have the right to resist the US invasion?

Preventive wars are intended to stop a potential future threat. The Iraq war in 2003 and the attacks on Iran are preventive. The difficulty is that it relies on speculation, which poses a high risk of abuse. It is difficult, if not impossible, to morally justify this type of war. You are attacking someone because of something they may do in the future.

Similarly, pre-emptive wars rely on speculation that the country was in imminent danger. The keyword is “imminent”. Once again, the moral justification is dubious.

When it comes to humanitarian intervention, such as in Rwanda and Kosovo, it comes down to sovereignty vs. the protection of civilians. Often, it is disguised as humanitarian but is really an attempt at regime change. Kidnapping the Venezuelan president was an attempt at regime change, if only to put his deputy in charge. Are the people of Venezuela any better off? Who knows. Trump does not seem in any way interested as long as the oil keeps flowing. After claiming it was humanitarian, he has done little to improve the lives of the people.

The case against invasion is that, without at least the threat of invasion, aggressors act with impunity within their own country.

Criteria for Moral Justification

Assuming there is a morally good reason for a humanitarian invasion, what are the criteria?

1. Just Cause

• Preventing large-scale atrocities
• No territorial expansion or resource acquisition

2. Legitimate Authority

• Ideally, United Nations Security Council authorisation

• Broad regional or international coalition

3. Right Intention

• Protection, not conquest
• Clear, public war aims
• Transparent legal basis

4. The Last Resort

• Sanctions, diplomacy, and mediation exhausted
• Evidence of genuine effort at peaceful resolution

5. Proportionality

• Harm caused must not exceed harm prevented
• Limited objectives
• Timetable and objectives defined

6. Reasonable Chance of Success

• Avoid symbolic or doomed interventions.
• Avoid creating failed states.

7. Clear goals

If invasion is morally defensible, what must its aims be?

• Stop aggression or atrocities.
• Restore sovereignty or protect civilians.
• Limited and defined objectives.
• Exit strategy and reconstruction plan.
• Avoid permanent occupation unless internationally supervised.

Too often, we see mission creep, regime change beyond the initial mandate and exploitation of resources. Trump claims he wants to stop the war in Ukraine, which is a humanitarian approach. He also wants to exploit the rare earths, which is neither moral nor supports his humanitarian argument.

Conclusion

So, can an invasion ever be justified legally? It can if the UN gives its stamp of approval, or it is the defence of a country. To accept the legality of UN approval, we must respect the UN’s authority and trust its decision-making process. As pointed out, this process is flawed and biased towards the permanent members of the Security Council. Unfortunately, we do not have an alternative at this point.

Can an invasion be accepted as a moral choice? We have put forward two situations where it may be justifiable morally. The first is where a country itself is under attack and invades the attacker as part of its defence.

The second is for humanitarian reasons. The humanitarian invasion is much more complex. Assume a case is made that a limited operation in Rwanda is morally justified as long as it meets all the criteria relating to being a just cause, has the right intentions, is a last resort, is proportionate, has a reasonable chance of success and has clear goals for the invasion and exit.

What of other countries with similar crises, such as Sudan, or the Tamils in Sri Lanka, or the unrest in China, with Uyghur Muslims being persecuted? The Rohingya are an ethnic and religious Muslim minority in Buddhist-majority Myanmar, and have endured decades of violence and discrimination. In 1990, inter-ethnic tensions escalated in Bhutan, resulting in the flight of many Lhotshampa, or ethnic Nepalis, from Bhutan to Nepal, many of whom were expelled by the Bhutanese military.

There was an exodus of between 100,000 and 200,000 Krajina Serbs during and after the Croatian Army’s Operation Storm. Some investigators and academics describe this event as ethnic cleansing. The War in Tigray has been described as an ongoing ethnic cleansing perpetrated by Ethiopia against ethnic Tigrayans. Ethiopia has also weaponised famine as a key war tactic in Tigray, leaving an estimated 90% of the population vulnerable to famine. All electricity has been cut off by Ethiopia, disrupting Tigray’s communication with the outside world.

I could go on, but the point is that humanitarian wars are selective. There is usually another reason for the war. In Rwanda, the colonial powers sought regional stability and feared a refugee exodus into their own countries. The US had recently been burnt in Somalia (Black Hawk down), and specifically would not label Rwanda as genocide. It would have been a legal obligation to act in accordance with UN rules.

In summary, Invasion may be morally defensible only under extremely narrow, clearly defined conditions, with strict limits and legitimate authority. For humanitarian invasions to be morally acceptable, there must be:

1. Protection of Civilians

• Prohibition of targeting noncombatants.
• Compliance with the Geneva Conventions.

2. No Annexation

• Territorial conquest violates the principle of sovereignty.

3. No Collective Punishment

• Distinguish regime from population.

4. Time Limitation

• Temporary use of force.
• Clear transition plan.

5. Accountability

The current Iran War fails on most fronts – both legal and moral.