Should adolescents be treated as adults under the law?

The idea that adolescents should be treated as adults under the law is inane. The adolescent brain is not yet fully developed. The prefrontal cortex, which is the part of the brain which deals with judgment and danger, does not fully develop until one is eighteen. As a result, it would be unfair to treat teenagers under the law as adults when they do not have the same opportunity to be a good judge. It would be akin to treating insane people as sane under the law, even when they cannot understand the difference between right and wrong. Overall, it would not be a good idea.

Another caveat is that it would make teenagers second-class citizens. They would have no right to vote, no right to serve on a jury, no right to open a checking account, and no right to do virtually anything without parental consent (pick the school they want, go to another country, etc.). Despite this, they could still be prosecuted under the law beyond the absolutely necessary degree under laws in which they have no say in making. Put together, and this could be a potential violation of the Due Process Clause of the Fourteenth Amendment.

In addition to that, if teenagers were to be given the death penalty, it would be a blatant violation of the 8th Amendment and human rights. If we ever executed someone who was under eighteen or even for crimes which were committed when they were under eighteen, the United States would be denounced worldwide as an authoritarian, cruel human rights violator. That would make our long-time allies especially eager to help us out, right? Not only would it violate the U.N. Convention on the Rights of the Child (which, aside from Somalia, which literally had no government at the time, the U.S. is the ONLY country in the world which did not sign it), but it would put us along with the only five countries would use the death penalty: Iran, Nigeria, Pakistan, Saudi Arabia, and Yemen. Remember when Iranian teenagers were put to death for sodomy which they allegedly committed when they were thirteen and how there were even a few sanctions imposed on them. You think because we're the superpower, that means that can't happen to us? Think again. Also, can you see on Taliban recruitment posters "America executes Muslim teenagers who support our cause". Wouldn't that help us win this "War on Terror"?
Adolescents are not given the same rights as adults. It would be inherently unjust to give them the same responsibility as adults. With freedom comes responsibility, but with responsibility comes freedom.