Yes, whenever strong and probable false statements are made against ISKCON are made, we can take defamation case against them
(S.P Letter to: Jayapataka Vrindaban 28 September, 1976)
NOTE: The real ISKCON is Srila Prabhupada, his teachings and genuine followers. So from this quote and the one below (S.P.Room Conversation on New York court case  November 2, 1976, Vrindaban) it is clear that our duty is to combine and bring a defamation case against Windle Turley. They are claiming that Srila Prabhupada is a duplicitous leader of a child molester cult. This claim has no basis and can easily be refuted in a court of law. If we bring a defamation case against them this will be the perfect way for us to completely seperate Srila Prabhupada and his transcendental movement from the child molester cult, which is posing as ISKCON. If we cooperate together to defend Srila Prabhupada's honor Krsna will help us to fully expose this whole poison tree. Everything can come out into the public, including Srila Prabhupada's torture and poisoning on to death by the cult leaders. Maybe this will be our last chance to cooperate and make a real stand against this sinister movement and prove to Krsna that we have some sincerity and love for His dear servant Srila Prabhupada. If we can not cooperate and work together due to our lack of love for Srila Prabhupada, at least we should act out of our own self interest. Sastra clearly says that inaction on our parts when a devotee or the Lord is blasphemed will lead to perpetual life in hell.
One who hears blasphemy of the Supreme Personality of Godhead or His devotees should immediately take action or should leave. Otherwise he will be put into hellish life perpetually.
(S.B. 7.1.26)
NOTE: Unless we commit suicide and leave this planet it is going to be difficult for any of us to avoid hearing this blasphemy of Srila Prabhupada, and it will continue to be broadcast more and more all over the world once the Windle Turley case begins.
Gopala Krsna: We want to defeat these people legally because now it's a very big case and every paper in America is covering it. Every paper.
Prabhupada: That means they're feeling pressure. They're feeling pressure. Now we should take proper steps, that's all.
Gopala Krsna: They had a big press conference in which Prof. Sukla spoke up...
Prabhupada: Hm. He has written very nicely.
Gopala Krsna: Ramesvara said he got up and he said "How can... You are insulting our religion..."
Prabhupada: Yes. Yes, better that the Indians
(NOTE: Genuine followers of Srila Prabhupada) should combine and they should bring a case against these people.
Gopala Krsna: Yes.
Prabhupada: And then it will be alright. That this is, Krsna consciousness movement is genuine,
(NOTE: The real ISKCON with Srila Prabhupada at the center as the spiritual master is genuine) and these people are trying to insult us. Bring a defamation case against these persons.
Gopala Krsna: I think the best thing is to mobilise all the Indians in America because every country...
Prabhupada: Yes, that I have already suggested, that they should take signature from all Indians that this is genuine Indian cultural movement and it a great fortune for Indians. They were bereft of their own culture and now we have got this culture again. The Ratha-yatra is going on, we are so much enlivened. In this way they should file petition.
(S.P.Room Conversation on New York court case  November 2, 1976, Vrindaban)