Does International Law only apply to countries that ratify treaties and accept the law?

Question

As far as I understand there are certain laws that compose a body of law called International Law. These laws arise from treaties and political bodies.

To provide an answer on this network aside from other controversial questions of politics and law when people make statements like the following,

And of course, there is no such thing as a "banned weapon". There are treaties that state signatory states aren't supposed to use certain weapons, but those are only valid if the country is a signatory and has ratified that treaty. – jwenting

And this,

Has Israel ratified any treaties which ban the use of DIME, AP bombs or WP? If not, then there's no "international law" for them to follow. BOTTOM LINE: the term "international law" is highly misleading. [...] - RonJohn

And this,

Well, you keep using the phrase international law, like it's a thing. If it's not the UN, then it is de-facto some random group of countries, and if Israel isn't a party to that group, it doesn't apply. If the UN (or some UN org) has actually made a law which is supposed to apply to all member nations outlawing DIME, AP and WP, then maybe Israel is beholden to follow it. My suspicion is there are no such "international laws". – CGCampbell

Is specifically the part in bold correct or not? It is my understanding that those that ratify these treaties do not merely accept them on behalf of themselves, but accept the responsibility to impose the law against others regardless of acceptance.

Would someone that has not ratified the Geneva Convention be immune to charges that the convention describes?

Answer 1

Law, as such, is not a moral or a philosophical construct. It can be based on moral constructs and often it is. And, of course, the process of writing laws is often informed by philosophy. But law as such is neither one of those.

Law is a set of behaviors which are known to be acceptable to the powers "that be." This maybe an unsettling idea. But it is true nonetheless.

The phrase that summarizes this is "any law is only as good as its enforcement mechanism."

What makes it seem untrue is that in the modern tradition laws are written down. And, when there is a need to resolve doubt as to whether something is illegal or not, they are carefully considered through a deductive process.

Within countries, there is little question who "the powers that be" happen to be. But when it comes to laws governing actions between nations, it is more complicated. Yes, treaties make it clear, ahead of time, what types of expectations exist.

Predictability (even in war) allows for long-term planning. And even laws of war are usually followed because wars are fought with the expectation that at some point they will end. And predictability allows to set end-goal conditions. Notably, entities which have no clear end-goals in sight are the ones least likely to follow any laws.

The idea of any group of countries sitting in court of another group of countries is mostly a political theater. There is no possibility of predictable outcomes from entities which have not made commitments to those outcomes. So whether some countries have to follow "laws" set out for them by other countries (or non-government entities) is largely a result of those countries or entities being in positions of power to dictate their will.

This is not the same as international laws being strictly de facto. Agreed-upon restrictions and restrictions which have been dictated from the top-down, by those with more power, are de jure because they create predictable boundaries on behavior. De facto restrictions are the ones which have come to be the case without any prior agreement or fiat.

Answer 2

"International law", to a great extent, isn't law in the sense that we talk about the law of a particular country. Much of it isn't litigated in courts.

Instead, an important subset of international law sometimes called "customary international law" is a set of maxims or principles that countries feel free to treat as binding obligations on other countries, sometimes even if they aren't signatories to any particular treaties establishing the obligation, to use as a basis for taking diplomatic or military action against another country, because they are widely accepted norms in diplomatic circles.

So, it isn't entirely true that a country has to agree that international law binds it expressly by a treaty or something similar, but that doesn't mean that there are legal processes by which to enforce a violation of customary international law either. Typically, customary international law violations are punished by diplomatic or economic sanctions, or by military action, or just by condemning the violator.

Treaties agreed to be a country are another source of international law, but as other answers note, enforcing treaty obligations against a country is often challenging and often a country's own domestic courts will not agree to enforce a treaty obligation when a dispute arises, especially when the treaty obligation applies to actions of the nation as a whole (e.g. recognition of the legitimacy of a boundary), rather than to how individual cases (e.g. treatment of foreigners for tax purposes) is involved.

Often domestic courts will treat alleged treaty violations as non-justiciable political questions, will conclude that a treaty is not "self-executing" or will otherwise abstain from ruling on a claim that a treaty was violated or will defer to the government of their own country regarding its obligations when there is a dispute regarding those obligations.

Many treaties provide no forum other than a signatory's domestic courts to enforce it, although others authorize international tribunals or arbitration forums to rule on disputes arising under the treaty. But even if there is a tribunal or arbitrator ruling, enforcing that ruling without the consent of a country that is supposed to be bound by it is very challenging in most circumstances.

Answer 3

Enforcement of any law requires someone with the ability and desire to enforce it. Enforcing the Geneva Convention implies either imposing sanctions on the violating country or military action against the violating country.

Any country can impose sanctions, for any reason they deem appropriate. Likewise they are, ultimately able to take military action against anyone they want to. Just how wise or effective either action would be, well, that’s another matter.

Economic or military action against the permanent members of the UN Security Council, regardless of justification, by non-members without the support of members, is probably going to be a bad idea. Even with such support it might end badly, with “bad” possibly going as high as the end or the world as we know it.

International law is countries regulating trade (aka normalizing the rules for how trade works) and war because trade benefits everyone and wars end and you have to get along afterwards, and you might lose.