Why did Israel fail to heed advance warnings of the Hamas attack, stop the breach of their Iron Wall and immediately repel the invaders from the Gaza envelope?

I have been reading things on the internet for a long time, and in that time I have noticed a pattern: Directly after a major geopolitical event, whether it is the invasion of Ukraine or the circulation of a virus or the explosion of a pipeline, a strain of commentary emerges that what we are seeing is in some sense illusory. I don’t want to say that such hypotheses are necessarily wrong; we live in a complex world, and wherever armies or intelligence services are at work our knowledge will always be imperfect. Nevertheless, I think recurrent hypotheses which adhere to identifiable patterns are worth scrutinising.

The security and intelligence failures attending the 7 October Hamas attack on Israel, since the first days after the war, have inspired a variety of theories in this genre, ranging from the overtly conspiratorial to the mundane. I have now spent some time reading these theories and studying the evidence which underpins them.

This evidence falls into four categories:

1. Hamas training videos, which appear to foreshadow many aspects of the attacks, and which Hamas took no steps to hide and in fact eagerly publicised since 2020. The argument is that the attack was planned in the open and that Israel did nothing about it.

2. Freelance photojournalists employed by news services like the Associated Press and Reuters, who accompanied Hamas militants on the morning of 7 October and documented the attacks. The argument is that if even news services had early knowledge of the action, it is hard to see how Israel didn’t.

3. A great many intelligence warnings in advance of 7 October, from within Israel, from the United States and from Egypt, that Hamas was planning a major attack. The argument is that Israeli intelligence services must have deliberately disregarded these reports.

4. The success of the attacks despite the sophisticated “iron wall” that Israel constructed around Gaza after 2006 and substantially upgraded in 2021; and the delayed, chaotic Israeli response to the attackers. The argument is either that Israel could have prevented the attacks or ought to have swiftly quashed the attackers, but did not.