ABSTRACT: After re-reading the series I was wondering if the DADA jinx could be the cause behind most of what happens to Harry in Hogwarts. Did it spark the chain of events that led to Quirrell's demise? Was Ron's wand broken in order to make Lockhart leave at the end of the year? Just how powerful was this spell?
As everyone who has read the Harry Potter books knows, during Harry's time at Hogwarts no Defense Against the Dark Arts (DADA) teacher lasted more than a year. In the first few books, we are told that there are rumors about the position being cursed, and later we learn that this had been happening since Dumbledore refused to give the job to Lord Voldemort. Dumbledore suspects that this was the moment the Dark Wizard jinxed the position. Later, in a chat after the release of the seventh book, JK Rowling herself confirmed that after the death of Voldemort the jinx lifted. But now that the series is over we can look back and see how important this spell actually was. Was it actually the cause of most of Harry's troubles?
In the first book, the DADA teacher is Quirrell, who previous to this point was the Muggle Studies Teacher. At the end of the year, we learn he has been serving Voldemort and trying to get the Philosopher's/Sorcerer's Stone in order to restore his master to power. As they - servant and master - share a body at the climax of the novel and Voldemort cannot stand the touch of Harry, Quirrell is therefore killed and the jinx fulfills its duty, emptying the teacher's position. But could all of what happens in the book have actually been caused by the jinx? After all, if the Stone hadn't been moved to Hogwarts exactly that year or if Quirrell hadn't met Voldemort in Albania or if Harry hadn't reached the Mirror of Erised and got the stone, Quirrell wouldn't have died and he could have continued teaching the subject. Was it the DADA jinx that put this into motion - this whole sequence of events that led to Quirrell's demise?
Next year, the unforgettable Lockhart is Hogwarts' new DADA teacher. The reason for his departure was that his memory spell, intended to erase Harry and Ron's memories about the Chamber of Secrets, backfired because he cast it with Ron's broken wand. And again, the question surfaces. Was Voldemort's jinx behind it? Did it cause Ron's wand to break originally at the beginning of the year? One could argue that it was all bad luck, that Lockhart just happened to end up with Harry and Ron down in the Chamber and that he tried to attack them. But knowing that there's magic making things happen so that a teacher can't last more than a year, it's worth giving some thoughts on what events can actually be caused by said magic...
Lupin resigns at the end of the year when Snape accidentally tells all the Slytherins that he is a werewolf. Before that, the great majority of the students loved his classes so it's safe to assume he would have continued as the DADA teacher. But when the climax of the book happens, all of the events lead to Snape telling his students the truth about Lupin's condition. The Potions Master encounters Sirius Black, an old enemy of his, and is convinced that Lupin has helped the runaway. He plans to give both men to the dementors but the trio knocks him out. He misses Pettigrew's transformation because of this and is still convinced Sirius is a criminal. So when Harry and Hermione use the Time-Turner to save Sirius and Dumbledore argues that Lupin's involvement was only trying to save the kids, Snape loses his temper completely and reveals Lupin's secret. How was the jinx involved here? Did it cause the entire chain of events (Sirius getting the newspaper and seeing Wormtail, escaping, attacking the trio, Lupin seeing them in the map, forgetting to drink the Wolf's Bane Potion, etc)? Or did it simply make Lupin forget to drink his potion, or make Snape want to follow them into the Shrieking Shack? It would seem Voldemort's jinx might be able to shape reality, or even a person's free will.
Moody/Barty Crouch Jr., in Harry's fourth year, was always supposed to stay only one year. But there's also a series of events that lead to the climax of the book (and, perhaps, the turning point of the entire series) that involves the DADA professor, which eventually make it impossible for him to ever teach at the school again. Was this also because of Voldemort's jinx? Next year, the Ministry would have wanted Umbridge to stay longer, if it hadn't been for the Minister finally seeing Voldemort and accepting his return. As for Snape, in the sixth novel "the Unbreakable Vow", Malfoy joining the Death Eaters and Dumbledore being cursed all led Snape flee the castle by the end of the book, ending his time as DADA professor, too.
How much of all this was actually caused by the jinx? Could it be the main reason behind most of the Potter series' events? After all, the DADA teacher is always somehow involved in the climax of the book and his departure is a result of this climax, a truningpoint that in itself is brought to fruition by a long streak of other happenings. It is interesting to consider how influencing this jinx actually is. Upon revisiting the books, one can argue that if it hadn't been for Voldemort's jinx not much of what happened would have actually happened. Maybe one day the great Jo Rowling will clear this up for us.