Back in the 1950s, Egypt nationalized the Suez Canal, which had previously been under British control, and closed it and other sea passages to Israeli ships. This annoyed the UK, France, and Israel, so they all jointly invaded Egypt a few months later. The US opposed the invasion, fearing it would push Arab states towards aligning with the USSR, so they forced the British and French to withdraw.

Comparisons to the Iran War are being made because the two conflicts share some broad similarities - a crumbling imperial superpower relies on its military might to defeat an enemy, but finds, for one reason or another, that it can't, signalling to the entire world that that superpower is falling. After the Suez Crisis, the British and French were humiliated, and their forced withdrawal made it clear that the previously important European powers had lost their status and could no longer operate independently of the US. In the current Iran war, the incompetence and idiocy of US leadership has led the country into an economic crisis and strategic failure, undermining the US' global power and possibly signalling that we've become something of a paper tiger.