A few days ago, the leader of a movement that wants its own state asked me how to get one. It was not of course an easy question to answer. But having been involved in various self-determination struggles around the world, I told him what I’ve learnt. Lessons about self-determination – becoming a state – are drawn not from academic studies, legal analysis or books... but from gritty experience. My organisation, Independent Diplomat, and I have advised two of the last three countries that have become independent, Kosovo and South Sudan (the third to become independent most recently is Montenegro). I’ve advised the governments and parties of some that so far have failed to win that goal: Palestine and Catalonia. I’ve worked for or talked with leaders and activists in West Papua, Kashmir, Western Sahara and Somaliland and even the South Tyrol. Indeed I’ve attended the UN Security Council with no less than five such movements. I was once a British diplomat there, so I’ve enjoyed both the first-class cabin and the cattle class treatment – and being refused entry.

This last experience points to the first lesson, a hard one for aspirant states to hear. Turkeys don’t vote for Christmas (or Thanksgiving). The state-based international system is profoundly ill-disposed towards new states. Perhaps this isn’t surprising. Many states, from Niger to Spain, worry about breaking up. Governments and rulers don’t like having less to rule over. People can be very discomfited by the prospect of “secession” – especially if their own rights are in question.

But it doesn’t work to simply dismiss powerful sentiments, a dismissal too often expressed in repression. The British government’s decision to allow a referendum on Scottish independence was exceptional and wise.

Contrast it with Spain’s punitive response to Catalan nationalism: several of those who organised a peaceful vote in Catalonia remain in jail. In every case of self-determination (with perhaps the exception of Palestine), the state-based system was, from the first outset, hostile. In Kosovo and South Sudan, the basic predisposition at the UN, EU and in other bodies was negative, until it wasn’t (and we’ll come to why it changed later, and Kosovo is still not a UN member state). In both cases, there was a painful and tortured diplomatic process to reach a conclusion that was obvious to anyone who lived on the ground: both states had to come into being or there would be war.

As a result of this systemic hostility, the second lesson is obvious: there is no application process to become a state. There is no committee or UN process to examine such cases. There is no website to explain how it’s done. Each case is different. But in short, you only become independent by pushing for it yourself. No one will give it to you even though, ultimately, it is other states who must recognise you as a state (the basic paradox that is the heart of the problem): unilateral declarations of independence achieve little and often provoke yet more resistance.

And because the process is not institutionalised, self-determination in practice, if not in theory, has very little to do with law (except in some strange cases). There are lots of voluminous legal texts about the criteria for statehood, the Montevideo Convention and so forth. But I’ve seen these to be largely irrelevant, except as tools for retrospective analysis. The choice to recognise a state is always a political one by other states. International courts don’t take the decision, though their rulings can confirm the necessity of a decision (as the International Court of Justice has done in the case of Western Sahara). Legal arguments can bolster political ones, but they are never primary. We once advised the Kosovo government not to circulate a paper on its legal case for statehood. Why? Because it was so weak. But Kosovo’s political case was strong: the overwhelming majority of its population wanted independence and the province had effectively been governed separately since 1999.

In one strange case, however, the law really mattered. But it wasn’t international law. In the case of Montenegro, Serbia and the rest of the world accepted Montenegro’s independence referendum, and subsequent independence, because of Montenegro’s status as a republic in the constitution of the short-lived state of the Federal Republic of Yugoslavia, a state that no longer exists, a status that in turn derived from the Tito-drafted constitution of the communist federation of Yugoslavia. Kosovo did not enjoy such a constitutional status, although it was part of the country, which was one of the arguments Serbia deployed to oppose its otherwise equally legitimate demand for independence. One necessary conclusion, the third lesson: law does not, and should not, define legitimacy.

You could fill a library with the UN resolutions demanding a Palestinian state – and yet it’s not independent

Fourth, and this is a hard one for liberation movements to hear: the state that matters most in self-determination is the one you are leaving. For Catalonia, Madrid’s ferocious opposition to any process of self-determination has effectively scuppered it, at least for now.

For Somaliland, the main obstacle to its recognition by other states, who are otherwise very complimentary about Somaliland’s remarkable self-built democracy and stability, lies in Mogadishu. And it doesn’t take an expert on the Middle East to observe that the country that matters most in Palestine’s fight to become a state is, of course, Israel (followed a close second by the United States).

Fifth, and this is more welcome to liberation movements: never give up. For decades, statesmen and so-called experts opined that East Timor would never win independence from Indonesia. East Timor’s leaders, when they weren’t in jail but in exile, would tour the corridors of places like the UN, receiving at best polite brush-offs and outright indifference (I’ve experienced the same many times). They never gave up. And today East Timor is independent. I’ve met the brave leaders of West Papua, a place that should be freed of the same oppression that the East Timorese endured and one day, I trust, will be. They’ve heard that lesson too. I don’t see Kashmiris giving up either: at a minimum, the maintenance of their struggle demands some kind of resolution. This will not go away.

Sixth, the commitments of the “international community”, such as those like international law, don’t count for much. You could fill a library with the UN resolutions demanding a Palestinian state, including General Assembly resolution 67/19 11317 that gave Palestine a sort-of membership of the UN and the ur-resolutions 242 and 338 that ordained the so-called two state “solution”, and yet Palestine is not independent.

In Western Sahara, the UN Security Council agreed there should be a referendum for self-determination in 1991 and has repeated that commitment on an annual (and sometimes six-monthly) basis ever since. An expensive UN mission was set up and remains to administer that referendum. The “international community” i.e. the powerful countries that run the UN known as the P5, have done nothing to fulfil its own commitment. Not with any pleasure, I’ve told Palestinian friends many times: it’s a great mistake to think that just because “they” have promised your own state, that “they” will one day live up to their obligations and grant you one. It doesn’t work like that.

Seventh, in all recent cases of contested self-determination, the United States is crucial. Kosovo and South Sudan became independent because the US decided it so, and brought the rest of the international community with them. If the US decides that it’s time for a truly independent Palestinian state – as it should – then my guess is that it would happen. In this realm, the multi-polar world has yet to manifest itself – at least not yet. As a sort of counter to Kosovo, whose independence Moscow formally opposed (but in fact privately acquiesced in), Russia encouraged the independence of Abkhazia and South Ossetia. Those would-be statelets have been recognised by a grand total of five other countries, including Russian satraps Venezuela and Syria. But whether the determinative importance of the US will endure its current decline of influence is another question.

Finally, the worst lesson of all.

Somaliland is a democracy and a beacon of stability in the wartorn Horn of Africa. It has a strong legal case for statehood as it pre-existed the creation of Somalia. Its population has voted overwhelmingly for independence. It has peacefully demanded its acceptance as an independent state since 1991 (and indeed it was once an independent state after the British left). It has been recognised by precisely nil other states and suffers the indignity of being called a “breakaway” state by the BBC, as if this word defines it.

None of the countries concerned would admit it, but it was the violence that triggered the process that ended with Kosovo’s declaration of independence

The Frente Polisario, which represents the indigenous people of occupied Western Sahara, has pursued nearly 30 years of peaceful yet fruitless diplomacy to demand the fulfilment of the international community’s promise of a referendum on self-determination. In all that time, it has refused to return to a liberation struggle by military force, despite many provocations including the purported annexation of the territory by Morocco. They have shown depthless patience and commitment to a peaceful resolution. The result? No referendum and little prospect of one. The Frente Polisario and 175,000 refugees driven out by Morocco in 1975 remain in refugee camps in the Sahara desert.

One New York morning, shortly before South Sudan’s independence referendum, the result of the ceasefire agreement that ended Sudan’s long and incredibly bloody civil war, the UN Security Council held what’s called a formal meeting to endorse the vote. It was attended by luminaries like Hillary Clinton, then the US secretary of state, and the UN secretary-general. I was there with a South Sudanese leader of the Sudan People’s Liberation Movement (SPLM) who was invited to speak in that grandiose forum. By coincidence, that same day, but in the afternoon, the Security Council met privately in so-called “informal consultations” to discuss, and do nothing about, Western Sahara. The Frente Polisario was not invited to speak but waited with them outside the private chamber. The SPLM leader stopped by and I made introductions: two liberation leaders meeting, both former guerilla fighters, both demanding independence. The first question the Saharawi representative asked of the South Sudanese was to the point: why did you get your independence referendum and we didn’t? The SPLM leader did not hesitate before replying: because we told everyone, very clearly, that if we didn’t get it, we would go back to war the next day.

Some lesson, but the very same I had learned in Kosovo. There, the UN Security Council refused to do anything about Kosovo’s final status for several years after the Nato intervention that ended Serbian control of the province in 1999. There was a lot of talk but no movement to resolve the question of the independence sought by the majority Kosovo-Albanian population. In 2004, there were deadly riots in Kosovo that were caused, in part, by the intense frustration over that lack of progress. Fourteen people were killed. The province seethed with violence. Various senior officials from the US and EU visited with grave faces. I was there at the time (I had been seconded to the UN by the British government) and told them: make this place independent or you will get more of this, and worse. Others said the same. None of the countries concerned would admit it, but it was the violence that triggered the “final status” process that ended with Kosovo’s declaration of independence in 2008.

The lesson could hardly be clearer, but perhaps needs spelling out. There needs to be some kind of international consensus and forum to address the many, and potentially violent, demands for self-determination across the world. The arbitrary drawing of borders by feckless and inept colonial officials in the Middle East, Africa and Asia has left behind an awful lot of unresolved self-determination crises. Kashmir, a source of conflict between two nuclear-armed countries, is not merely of local interest. We need some accepted criteria to assess the legitimacy of such demands, including for instance the protection of minorities, non-interference by outside powers and democratic endorsement (a requirement for non-violence might also help), and we need a place to talk about them sensibly. Not a court, as these disputes do not lend themselves to legal arbitration. They are political matters to be resolved by political means: negotiation, negotiation and more negotiation.

So this was the advice I gave the independence leader. He took it well, but gravely, for not all these observations were welcome. Although embroiled in war, he is a man of peace and reason. I didn’t relish telling him that the threat of war was decisive in the two examples of “successful” self-determination I’ve been part of, but it’s the truth. And in both those examples, the resulting states have been troubled and, in the case of South Sudan, horrifically violent, an outcome born of local rivalries: an example that is often carelessly deployed globally to dismiss all those who seek new states. But I’m sure he, like me, would prefer it otherwise – would prefer that there were some way of dealing with his demand for self-determination more sensibly and, above all, peacefully.

Carne Ross is founder of Independent Diplomat, the world’s first diplomatic advisory group