The Jedi had plenty of chances to find out the truth about the clone army and prevent Star Wars' Order 66 from happening. A redefining Star Wars event that continues to be referenced almost twenty years after Star Wars: Episode III – Revenge of the Sith, Order 66 explained how the thousands of Jedi of the Star Wars prequels were reduced to a few space wizards spread across the galaxy whose powers most did not know about or believe in. However, it was only in Star Wars: The Clone Wars that the specifics of what was behind Order 66 were revealed.
The Clone Wars made the clones into individual characters, which, for a Star Wars rewatch in chronological order, only adds to the tragedy of Revenge of the Sith’s Order 66 scene. The Clone Wars series builds from Star Wars: Episode II – Attack of the Clones’ ending and retroactively sets up several moments from Revenge of the Sith, including the clones’ ultimate betrayal and how it could have been prevented.