I don't know anything.
The simple phrase, "I don't know anything," much like the phrase, "This is all an illusion," can mean a lot of things. Context and inflection matter. So does knowing the person who is speaking.
"I don't know anything," could, be a declaration of innocence or and attempt to not incriminate oneself.
In the mouth of a philosopher or some one into metaphysics" I don't know anything," can be a declaration of wisdom.
If a person who meditates where others can see, says, "I don't know anything," it may be a declaration of superiority hidden as modesty.
It might be a phrase of comfort and agreement with someone who faces issues beyond their ability to sort out.
It could be a reply to a question that a person cannot answer.
"I don't know anything," could be the response to a moment of realization.
This list goes on and on but despite the twists and turns of this statement, most of us can see a place where we might say this. For a Republican, especially TFG, it is a statement you will probably only hear from them sometime after they have received a court order to appear.
Here is hope that we start hearing this a lot from the other side of the aisle.