Whether you trust WND's explanation may come down to whether you believe WND's writers would knowingly include unattributed references in their articles. Perhaps you would consider whether they had done so recently.
Take, for instance, Aaron Klein's December 9, 2011 article, "Naturalizer Newt: Gingrich's shifting views on immigration".
Now take this November 29th CNN editorial by William J. Bennett.
Now let's compare them:
CNN, Nov. 29:
Gingrich's call for a "humane" immigration policy in last Tuesday's CNN debate sounded too much like amnesty to many conservatives.Aaron Klein, Dec. 9:
During a CNN debate two weeks ago, Gingrich called for a "humane" immigration policy that would grant legality for an untold number of illegal immigrants, something that sounds a lot like amnesty to conservative critics.CNN, Nov. 29:
...only grant legality, not full citizenship, to anyone who has entered the country illegally should they meet stringent requirements.Aaron Klein, Dec. 9:
Although legality, not full citizenship, would be given to those who meet stringent requirements,CNN, Nov. 29:
Only those who can sustain themselves without government assistance (Social Security, Medicare, Medicaid, etc.) and pay for their own private health insurance would be eligible to stay.Aaron Klein, Dec. 9:
only those who can sustain themselves without government assistance and pay for their own private health insurance would be eligible to stay in the country with legal status.CNN, Nov. 29:
An independent, local "citizen's review" board would grant legal status based on the requirements above as well as the immigrant's standing in his or her community. Should they be permitted to stay, they will still be subject to a $5,000 penalty.Aaron Klein, Dec. 9:
...an independent, local "citizen's review" board that would grant legal status based on the financial independence requirements and the immigrant's standing in his or her community. Each individual permitted to stay would be subject to a $5,000 penalty.And finally, the real kicker, the word-for-word swipe:
CNN, Nov. 29:
...full control of the border by January 1, 2014. All government resources necessary would be made available for this, including "round-the-clock drone flights" and "multi-layer, strategic fencing in urban areas."Aaron Klein, Dec. 9:
...full control of the border by Jan. 1, 2014. All government resources necessary would be made available for this, including "round-the-clock drone flights" and "multi-layer, strategic fencing in urban areas," Gingrich says.Now admittedly, this is hardly the worst case of unattributed borrowing out there. But Klein clearly cribbed from Bennett's editorial, borrowing word choices and sentence structure and even whole phrases, and there is no link or attribution to either Bennett or CNN.
More importantly, this was published on WND on December 9, just ten days before Corsi's article that similarly (but more blatantly) swiped from the London Evening Standard and the AFP. So how much benefit of the doubt do you want to give WND in believing their story about "Kenyan researchers" being to blame for Corsi's conduct? Are "Kenyan researchers" also to blame for Bennett's words showing up in Klein's article?