They're a global superpower. They're a bunch of bastards, except when compared to any other great power in human history. Including the British Empire, France, Germany, Spain, Russia etc.
The British Empire were ones that led the coup of Mossedegh btw. The British rightfully, to my knowledge, owned the Anglo-Iranian Oil Company (AIOC), and Iran sought to nationalize those assets which the British owned. The problem was that Britain also thought they owned Iran's oil because they discovered and developed it. The other problem was that Mossedegh not only thought Iran owned Iranian oil, he thought Iran owned the British assets like the AIOC on Iranian soil. In a perfect world they should have brokered a deal where Iran could purchase certain infrastructure or corporate assets from UK. But Britain was still in empire mode and was broke from WWII, while Mossedegh was a bit greedy.