The Rise and Fall of Darth Maul
Emperor Palpatine rarely made mistakes in Star Wars, but his treatment of his former apprentice Darth Maul was one of his biggest. Maul was Palpatine's first apprentice, but his time as a Sith was cut short by Obi-Wan Kenobi in Star Wars: Episode I - The Phantom Menace. Though Maul was presumed dead, he survived his duel with Obi-Wan and later began his quest for power on his own. Maul was a prominent villain throughout Star Wars, but he didn't discriminate in his choice of opponents. He had a deep and hateful relationship with Obi-Wan, but he also threw a wrench into many Sith and Imperial plans. Most notably, he helped Ahsoka Tano escape from Order 66 during the Siege of Mandalore. His various targets came from his long history of being beaten and betrayed, but they also showed that Maul was only interested in advancing his own goals. That selfish quest for power proved to be one of Palpatine's greatest failures.
Darth Sidious fighting off Maul and Savage Opress at the same time in The Clone Wars.
In the later seasons of Star Wars: The Clone Wars, Maul became one of the major power players in the galaxy. Even in the midst of an ongoing war, the Jedi devoted resources, troops, and several masters to hunting him. He eventually took control of Mandalore by overthrowing and killing Duchess Satine Kryze. Palpatine's plan hinged on controlling both sides of the war, both the Republic and the Separatists. Maul introduced a third variable into the mix, one that could have disturbed the careful balance Palpatine was trying to maintain. Palpatine confronted Maul and his new apprentice, Savage Opress, easily killing Savage, defeating Maul, and showing his true power. At the beginning of his confrontation, Palpatine told Maul 'You have become a rival.' Maul's plans and influence over the galaxy proved that he was a force to be reckoned with. Palpatine's mistake was underestimating Maul and abandoning him after The Phantom Menace. All Palpatine could see was a mortally wounded failure, when Maul still had so much left to offer. If he had healed his former apprentice, Maul's power could have helped him for years, but instead they went against his plan and inspired Maul to eventually plot against Palpatine.
Palpatine in THe Rise of Skywalker and Darth Maul in The Phantom Menace
Maul's Example and Palpatine's Lesson
Palpatine was nothing if not cunning, though, and he learned from his failure with Maul. Once he saw how powerful Maul truly was, he used him at the most crucial moment of his plan to destroy the Jedi. Maul distracted the Jedi and took Ahsoka, one of the few people who could get through to Anakin, out of the larger war with the Siege of Mandalore. Though he wasn't Palpatine's apprentice anymore, Maul still served the dark side. Palpatine's mistake was underestimating Maul and abandoning him after The Phantom Menace. Palpatine also took the lesson he learned from Maul forward. At the end of Star Wars: Episode III - Revenge of the Sith, Darth Vader was in a similar situation to Maul: defeated, wounded, and on the brink of death. Palpatine didn't leave Vader to his death as he did with Maul, though. Instead, he fixed Vader and turned him into his puppet from the start. Because of the lesson Palpatine learned from his past mistake, Vader became the perfect weapon of the Empire. In order to overthrow the Jedi and establish the Empire, everything in Palpatine's plan had to work perfectly. Maul's survival and personal goals to gain power threatened that plan. Palpatine didn't make many mistakes in Star Wars, but his underestimation of Maul proved to be his greatest failure until his final mistake that cost him his life.
Conclusion
Emperor Palpatine's rare mistake of underestimating Darth Maul proved to be a pivotal moment in the Star Wars saga. It was a mistake that cost him dearly, as it allowed Maul to become a powerful rival and a force to be reckoned with. Palpatine's failure to recognize Maul's potential and the threat he posed led to a series of events that ultimately challenged Palpatine's grand plan. However, Palpatine's ability to learn from this mistake and apply the lesson to Darth Vader demonstrates his cunning and adaptability. In the end, it was Palpatine's underestimation of Maul that proved to be his greatest failure until his final mistake that cost him his life.