Witches don't need lawyers...

Danforth claims that witches don't need lawyers, because witchcraft is an invisible crime:

Hale: Excellency, I have signed seventy-two death warrants; I am a minister of the Lord, and I dare not take a life without there be a proof so immaculate no slightest qualm of conscience may doubt it.

Danforth: Mr. Hale, you surely do not doubt my justice.

Hale: I have this morning signed away the soul of Rebecca

Nurse, Your Honor. I’ll not conceal it, my hand shakes yet as with a wound! I pray you, sir, this argument let lawyers present to you.

Danforth: Mr. Hale, believe me; for a man of such terrible learning you are most bewildered - I hope you will forgive me. I have been thirty-two year at the bar, sir, and I should be con-founded were I called upon to defend these people. Let you consider, now - To Proctor and the others: And I bid you all do likewise. In an ordinary crime, how does one defend the accused? One calls up witnesses to prove his innocence. But witchcraft is ipso facto, on its face and by its nature, an invisible crime, is it not? Therefore, who may possibly be witness to it? The witch and the victim. None other. Now we cannot hope the witch will accuse herself; granted? Therefore, we must rely upon her victims - and they do testify, the children certainly do testify. As for the witches, none will deny that we are most eager for all their confessions. Therefore, what is left for a lawyer to bring out? I think I have made my point. Have I not?

Hale: But this child claims the girls are not truthful, and if they are not -

Danforth: That is precisely what I am about to consider, sir. What more may you ask of me? Unless you doubt my probity?

Hale, defeated: I surely do not, sir. Let you consider it, then.

1.  Explain Danforth's argument in your own words.  

2.  Do you think it is valid?  If not, how would you convince Danforth otherwise?