system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How are the courts able to try a minor as an adult?

I always thought law was pretty rigid, so if someone is a minor and they're being charged with a crime, they would be tried as a minor. However, there are many cases where a minor gets tried as an adult. How do they do this? What's the law that allows them to do it, and is it only with specific crimes?
gpt
IANAL so pinches of salt.

It's basically a matter of severity, intent, and the individual circumstances.

Consider 2 hypothetical incidents involving a minor (Lets say about 7-9 years old).

In the first, a kid somehow gets hold of a gun, and shoots someone they don't like - killing them in the process, but makes no effort to hide or destroy any evidence. When interviewed and asked why they did it, they either don't really know why they did it or didn't think it'd kill them (they'd go to hospital and get better).

In the second, the kid keeps a diary where they detail and plan killing someone they don't like. How to get the weapon, where the target goes, how to cover up their tracks - the entire thing is pre-meditated and planned to deliver the result. They know they're doing something wrong and plan to evade getting in trouble for it.

The reason we separate trials for minors and trials for adults is because it's generally accepted that children have less understanding of the consequences and severity of their actions, and as such need to be handled differently. In the second example, they've demonstrated through their actions that they understood the consequences of their actions - and as such it may no longer be appropriate to try them as if they didn't.

There are also a few caveats that would apply more to children. If in the second example the person killed was an abusive family member, then despite the pre-meditation and understanding of consequences they'd be more likely not to be tried as an adult since it's difficult for a child to escape abuse from a family member.

However an adult doing the same may be more likely to charged with manslaughter rather than self-defense (assuming they were not in immediate danger, and were reacting to a history of abuse by someone) as they are assumed to be better equipped to deal with the problem through legal means.

So that's for the why. The 'how' is basically a case of 'if it's necessary, then do so' - but a judge can't just turn around and decide to try a minor as an adult. There are a lot of checks in place that have to be satisfied before it can happen.