You make it sound like she's a legal neophyte. I'd say the fact that She has a Jurist Doctorate from one of the most prestigeous law schools in the world, passed the bar, Taught Law at the graduate level and managed a successful law practice and has crafted laws as a legislature and implemented the law as an executive in government is pretty solid proof she understands law. Probably just a weeee bit more than we do.
Most Supreme Court Justices have considerable bench experience. Hilliary has none.
Having said that, some of our best Supreme Court Justice did not have much bench experience.
My shirt tail relative William Howard Taft was a mediocre President but one of our best Justices on SCOTUS and he had little bench experience if any.