The claim is that internal CIA memos have revealed that Israeli intelligence groups pretended to be CIA agents for the purposes of recruiting members of the Jundallah (an Iranian terrorist organization) to help them with a covert war against Iran. The CIA itself has refused to have any interaction at all with the Jundallah because of the aforementioned terrorist activities.
So why am I suspicious? For a couple of reasons. The first is that the author of this story, Mark Perry, was the same author who wound a tale of General Petraeus blaming Israel for dead American soldiers in Iraq and Afghanistan. A tale that also provoked a Huffington Post hatefest, if you recall. He then did it again with a claim that America was engaging with Hamas and Hezbollah. It's a little funny how the same author just happened to break another potentially devastating anti-Israel story.
Secondly, there is no actual proof besides hearsay. The author cites internal CIA memos but doesn't link to them, so there's no way to check them for proof or any kind of context, we have to rely on the (not so trustworthy) author to interpret them for us. That's assuming that these memos even exist at all, which we do not know yet.
Finally, there's an internal consistency problem within the story. The CIA forbids contact with the Jundallah, and it goes without saying that the Mossad wouldn't tell us about these activities. So if that's the case, how did the CIA find out? There's no mention of any other intelligence group blowing the whistle, and I don't see how spy cameras or drones could have uncovered it. For the CIA to know about it they would have to be inside the Jundallah itself. But, according to the article, they aren't.
All this being said, if the story does in fact check out, Israel deserves to be punished by America in whatever way that the American government sees fit. Just like any other country doing the same thing.
Now, on to the Huffington Poster reactions! I'll ignore the usual attacks on Israel like "rogue state" and so forth, since even though that's exactly what the Huffington Post wanted it's understandable given the nature of the story on which the readers are commenting. What is less understandable is when certain Huffington Posters are given an inch, they take a mile. Some Huffington Posters saw the opportunity as an open door to accuse Israel of being behind 9/11 and other assorted levels of Jew-baiting:
I particularly like the "GOP candidates are Israeli agents" one.
Update: A more detailed analysis at The Empty Wheel.