Just a thought here; we are still on the internet. Can I see some actual proof that what is being asserted as having happened, actually happened (letter, member, etc. etc.)?
Email Kevin McCullough at the original article. He linked to some excerpts from the email. For obvious reasons, the submitter of the email has wanted to remain anonymous. But I imagine it's possible he would be the only one who could verify the email.
Joseph Farah at worldnetdaily has had a running tiff with Warren too since the Obama/Syria things, and he has been in correspondence with a Saddleback member expressing similar concerns.