I don't agree that domestic law always wins. It all depends on the situation.

If a country's domestic law violates international law, the extent to which that country gets away with it depends a lot on how powerful that country is. Great powers have much more ability to violate international law with impunity than small countries do.

And in this particular case, it is not that US law and international law are actually in conflict. It is just they assign different meanings to the same words. Even the US government generally accepts the internationally standard meanings in international fora.

Nations are sovereign they can do what they want. Short of going to war its hard to force a country todo something it does not want too. Although if you pull out of agreement don't expect the other country to continue following it.

Also there are other countries not part of this talk nothings stops a company from setting up there and doing the same tax games. So i dont see how this idea does anything

> Nations are sovereign they can do what they want. Short of going to war its hard to force a country todo something it does not want too

In today's world economic pressure is a much bigger factor than war. If you upset enough countries, they can all start imposing trade and financial sanctions on you, which then ruins your economy. International law is a useful (even though of course not always perfect) guide in answering the question "is doing X going to upset a large number of countries?"

> Also there are other countries not part of this talk nothings stops a company from setting up there and doing the same tax games.

Most of these companies are actually headquartered in major economies – US, the EU, etc. What they've been doing is exploiting complex loophole interactions between the tax laws of those major economies and the tax laws of small countries with favourable tax regimes. If the major economies close those loopholes, they can stop most of this. The small countries only get away with it because the major economy tax law loopholes let them. Most of the time, companies don't want to move their actual headquarters to these small countries due to the negative consequences

The major economies are also large sources of these loopholes.

Until 2020, Russian constitution had a provision that international treaties have a priority vs domestic law.

Which is how it should work in principle. Why would parties to an agreement care about each other's internal matters?

Without such a provision you open up to scenarios where a parliament sabotages international treaties by making laws that are in conflict with them.

That's worse than actual official termination of the agreement because the threshold is much lower.

In international law, this is known as monism vs dualism.

Monism says that international law and domestic law form a single cohesive whole. International law automatically applies domestically, and domestic law which contradicts international law is automatically invalid.

Dualism says that international law and domestic law are two independent systems. International law only applies domestically if domestic legislation is passed or amended to make it applicable. Domestic law and international law can contradict each other, and in cases of contradiction the domestic courts will follow the domestic law and ignore international law.

Some legal systems have adopted monism and others dualism. And yet others, like the US, are actually a hybrid – US law is mostly dualist but with a few monist elements.