One of the still unsolved mysteries of the September 11 attacks is how the foreign government that was by far the most responsible for that atrocity got off completely scot-free — and, in fact, proceeded to be lavishly rewarded by Washington for years to come.

If 9/11 was a modern Pearl Harbor, then imagine that Franklin Roosevelt had responded to that attack by covering up any evidence of Japan’s involvement, blaming and invading the Soviet Union instead, and then spending the next two decades selling the Japanese Empire billions of dollars in weapons, regularly wining and dining their leadership, and helping them commit war crimes in other parts of the world. This is basically what happened between the United States and Saudi Arabia since that day in 2001.

Even before the attacks, it was understood that, as part of the delicate balance of power keeping the royals in place at the top, the Saudi government was helping fund and export Islamic extremism around the world, in line with the wishes of the radical clerics by whose assent they ruled. The Saudi government was a distinctly unhelpful force in previous terrorism investigations, stonewalling US attempts to get Osama bin Laden and refusing US requests to arrest or execute him when Sudan offered to hand him over. According to one US counterterrorism official, that would’ve meant “we probably never would have seen a September 11th.” Then there was the fact that most of the hijackers were Saudi nationals, as bin Laden himself was.