How to Build Strong Arguments

A legal argument is a claim, a reason and proof. Judges want the claim first, the reason second and the proof third. If a judge must guess your claim, you have already lost marks.

Step 1: Decide your theory of the case

Before writing any argument, write your whole case in one or two sentences. This is your theory of the case.

Torsa’s theory: “The Rupa Water Treaty still binds Ulka because Ulka never gave proper notice, and even if the treaty ended, international law forbids Ulka from causing serious harm to a downstream neighbor.”

Ulka’s theory: “The treaty ended when Ulka gave notice, and a State may use the water inside its own territory in a reasonable way, so no harm rule was broken.”

Then test each argument: does it fit my theory? Arguments that pull in different directions confuse judges and let the other side attack you.

Step 2: Walls, and three ways past them

List every point you must win. Each point is a wall. For each wall, choose one of three routes.

Route	Meaning	Example (Torsa, on notice)
Over the wall	Accept the rule, show the facts satisfy it	“Article 12 needs written notice to the other party. An email to an official was never addressed to Torsa’s government.”
Around the wall	Say the rule does not apply here	“Even if the email counts as notice, Article 12 only works if notice is given a full year before expiry. It was late.”
Through the wall	Say the rule or the other side’s case is wrong	“A treaty that protects water supply cannot be ended by an unsigned message. That reading defeats the treaty’s purpose.”

Always deal with your weakest wall openly. Judges notice when you hide it.

Step 3: Argument models you can copy

Below are eight models. Learn them one by one. They are tools, not scripts. Judges dislike speech that sounds like a formula, so say them naturally.

Model 1: CREAC (the best model for memorials)

C=Conclusion: Say what you want the court to find.
R=Rule: State the legal rule, with source.
E=Explanation: Explain how the rule works (cases, treaty text, reasoning).
A=Application: Apply the rule to the facts of this case.
C=Conclusion: Repeat the result, now proved.

Example (Torsa, notice):

C: Ulka’s email did not terminate the Rupa Water Treaty.

R: Article 12 requires “written notice” one year before expiry. Treaty words are read in their ordinary meaning, in context and in the light of the treaty’s object and purpose (VCLT, Art 31(1)).

E: The object of this treaty is to protect Torsa’s water supply (Preamble). A step that removes that protection must be clear and formal. [Add authority on formal notice in treaty practice.]

A: Ulka sent an email to a ministry official. It did not go through diplomatic channels, no one replied, and it came less than a year before the treaty’s end. Torsa had no clear warning.

C: Therefore, the treaty renewed automatically and Article 4 still binds Ulka.

Model 2: IRAC (best for your own notes)

I=Issue: What is the question?
R=Rule: What is the law?
A=Application: How does the law apply to these facts?
C=Conclusion: What is the answer?

IRAC begins with a question. Memorials begin with an answer. So, use IRAC to think, and CREAC to write.

Model 3: Elements test (best when the law has a clear test)

Formula:

Element 1 satisfied + Element 2 satisfied + Element 3 satisfied = the rule applies.

Example (State responsibility, ILC Articles, Art 2): An internationally wrongful act has two elements: conduct attributable to the State, and a breach of an international obligation.

Element	Facts	Result
1. Conduct attributable to Ulka	The Ulka Water Authority is a state agency, so its acts count as Ulka’s (ILC Articles, Art 4)	Satisfied
2. Breach of an international obligation	The dam cut the flow below 40% (Treaty, Art 4)	Satisfied

Take the test apart, prove each part, then put it together. Judges like this because it is easy to follow.

Model 4: Treaty interpretation (VCLT Articles 31 and 32)

Formula:

Words → Context → Purpose → Later practice → Preparatory work.

• Ordinary meaning of the words. What does “written notice” mean in normal use?
• Context. Other clauses, preamble, annexes.
• Object and purpose. Why did the parties make this treaty?
• Later agreement and practice. Did the parties always send notices by post, or by email?
• Preparatory work (only if still unclear). Drafting history.

Use this model for every dispute about what a treaty clause means.

Model 5: Analogy and distinction (working with cases)

Formula (follow the case):

Case X + the key similarity + so the same result here.

Formula (avoid the case):

Case X + a difference that matters legally + so a different result here.

Example (Torsa):

“In Pulp Mills the Court said a State must act with due diligence and carry out an environmental impact assessment where a project may cause significant harm across a border. Ulka’s dam is a much larger project on a shared river, so the same duty applies with even more force.”

Example (Ulka):

“In Pulp Mills the shared river was a boundary with a treaty regime built for joint management. Here the treaty has ended, so that case does not decide this question.”

A difference only counts if you can say why, it matters legally. “The facts are different” is not enough.

Model 6: Consequence (policy) argument

Formula:

If the court accepts their rule → bad result → so the court should prefer our rule.

Example (Torsa):

“If an email to a junior official can end a water treaty, any upstream State could end a river agreement overnight. That would destroy trust in every river treaty in the region.”

Use this model as support. Do not use it as your only argument. Judges want law first and policy second.

Model 7: Alternative argument (the safety net)

Formula:

Primary case. Even if the court disagrees, second case. At the very least, third case.

Example (Torsa):

“First, the treaty is still in force and Ulka broke Article 4. Second, even if the treaty ended, customary law forbids significant transboundary harm. Third, at the very least, Ulka must pay for the harm it caused before it gave valid notice.”

Alternative arguments protect you when a judge rejects your main point. Keep them short and make sure they do not contradict your main argument.

Model 8: Anticipate, concede, answer (dealing with the other side)

Formula:

They may say A. We accept the part of A that is true. But B, so A does not win.

Example (Torsa):

“Ulka may say a State can use water inside its own borders. Torsa accepts that States have sovereignty over their territory. But sovereignty is limited by the duty not to cause significant harm to other States (Corfu Channel; Trail Smelter).”

Phrase this as “may argue”, not “will argue”, unless you already have their written submission.

Step 4: Choose arguments wisely

You will find many arguments. You cannot use them all. Score each argument with four questions:

• Source: Is it backed by a strong source?
• Fit: Does it match the facts and the issue?
• Consistency: Does it agree with our other arguments and our theory?
• Survival: Can it survive the toughest questions asked by judges?

Keep arguments that score well on at least three. Drop the rest. A short memorial with three excellent arguments beats a long memorial with ten weak ones.

Do not choose an unusual argument only because it is unusual. Choose the most persuasive route.

Step 5: Order your arguments

• Follow the logic of the law. If the court must first decide jurisdiction, begin there.
• Where there is no logic order, put your hardest point early. Judges will ask about it anyway, and you will have time to explain it.
• Within each issue, put your strongest argument first, then supporting ones, then fallback ones.

Step 6: Check whether your argument is finished

• Is the claim in the first sentence?
• Is there a source with a pinpoint?
• Did I apply the rule to our facts, not only describe the law?
• Did I say why the point matters for the final result?
• Did I deal with the best opposing point?