OKC + 10
Just a brief note. I took a [probably unhealthy] interest in that event for provincial reasons; I grew up in that part of the country, and had lived, worked, or visited in all the relevant locations from Fort Riley to Herington to Perry to OKC. Had a passing acquaintance with lawyer Stephen Jones; he had defended a friend of mine in Enid at the start of his career. Jones did a poor job for McVeigh, just as he had done for my friend.
As with the JFK assassination, you don't need a lot of fancy theories to be certain that the FBI stopped light-years short of the whole truth. With JFK, you only need to know that Jack Ruby was a Mafia hitman to explode the notion that Oswald acted alone. When you add the fact that Marina Oswald was allowed to emigrate with Lee, at a time when nobody got out of the USSR without an official purpose, you have all the info you need.
With OKC, you only need to know that Nichols spent long periods in the Phillipines without
his Islamic mail-order bride, to explode the notion that this was a purely domestic operation. When you add in the clear connections to the Elohim City group, you have all the info you need.
In each case it's clear that two groups with parallel goals, one foreign and one domestic, aided the 'lone gunman' to some extent. If you want to embroider beyond that (as several authors including Jones have done), well, there's bread and cheese upon the shelf.
UPDATE: Remarkable essay by Fox's John Gibson this afternoon. First time I've heard anyone in the 'solid media' declare outright that Saddam was involved.