Why doesn't a prosecutor charge Kavanaugh and Ford with perjury, because one lied under oath?

Then after their lawyers call witnesses and each pleads their case, let a court of law with a jury of peers decide which has committed perjury?

Added (1). Then the FBI could do a investigation, real, thorough and unlimited and they could each take a lie detector test from a same unbiased testing source

Is the FBI investigation to prove that Kavanaugh was lying to the judiciary board at the hearings?

There hasn't been a crime committed about which to lie. The foundation of a case would not make it to a court.

Burden of proof issue. "Someone lied" isn't sufficient proof to convict, a 36 year old memory can be flawed, and could not prove a deliberate attempt to defraud.

Life is not all that black and white

Both are politically motivated and politicians lie as a matter of course. Locking them all up would be an excellent idea, but there aren't enough jails.

You can't charge both and figure it out later. The law doesn't work that way. This isn't like putting two kids in time out if you can't figure out who started the scuffle.

Because that is not how it works. That is not how any of this works.

Because neither if them are on trial is why.