Challenge the evidence? What possible motivation would the defendant have to do that.
The defendant in this case has considered from day one that he would likely get caught. He also considered that he is guilty as charged. He is not interested in trying to beat the rap. He is interested in trying to justify what he has done.
How smart do you have to be to figure out this guys motivation. This is not about winning a case. It is about winning followers.. even at the cost of a murder rap.
Kopp doesn't have to be executed or get life to turn his trial into a stage for his politics.
If he gets acquitted, he could spend the rest of his life on a speaking tour - or writing books.