Chapter 12 of Harry Potter and the Order of the Phoenix: Professor Umbridge
The next morning begins nearly as frustratingly as the previous night ended. Seamus leaves the room as quickly as possible without speaking to Harry. Hermione says Lavender Brown doubts Harry’s story, as well.
At breakfast, there is still no sign of Hagrid. Hermione suggests that Professor Dumbledore has not mentioned it to avoid drawing attention to Hagrid's absence. Harry is braced by Angelina Johnson, who has been made Quidditch captain. With Oliver Wood gone, they need a new Keeper, and will be having try-outs on Friday. Angelina wants everyone there. Professor McGonagall hands out class schedules, which seem particularly strenuous this year. Fred and George offer their defective Skiving Snackboxes for a discount, then discuss their lack of concern for school. George mentions that they considered not returning to Hogwarts and says they will spend their last year doing market research for their joke shop. George hints that they have financial backing, sidestepping questions about where the money is coming from.
During a break in their morning classes, the Trio run into Cho Chang. She apparently wants to talk to Harry, but Ron insults her favorite Quidditch team, causing her to leave, and earning him a scolding from Hermione. Harry’s spirits are further dampened, both by losing a chance to talk to Cho and by his friends' bickering, as they head to Snape’s dungeon for Potions. Snape gives them a particularly difficult potion. When Harry misses part of the instructions, Snape singles him out and Vanishes his entire mixture, earning him no marks for the entire lesson. Luckily, the following Divination lesson is uneventful.
In Professor Umbridge’s classroom, students are instructed to put away their wands and take notes. Professor Umbridge announces that they will be learning a "Ministry-approved course of defensive magic this year." After giving the course aims, she instructs the class to read the first chapter in their textbooks, but Hermione sits defiantly with her hand raised until Professor Umbridge is forced to call on her. Hermione notes that there are no course aims concerning actually using defensive spells, to which Umbridge replies, "I can’t imagine any situation arising in my classroom that would require you to use a defensive spell." Instead, students will study the theory and perform the spells for the first time at their examinations in the spring.
A heated discussion ensues about the necessity of learning practical Defence Against the Dark Arts, in which Professor Umbridge rebuts Harry’s claims that Voldemort has returned as a lie. Harry reacts angrily, telling the class that Cedric Diggory was murdered, not accidentally killed as Umbridge stated. Harry is sent to Professor McGonagall’s office with a note detailing his detention. McGonagall sternly warns Harry to tread carefully around Dolores Umbridge—the Ministry of Magic is interfering at Hogwarts.
It is immediately clear that Dolores Umbridge is at Hogwarts for some reason other than teaching Defensive Arts. That she was personally appointed by the Ministry strongly indicates that she is probably there to represent their interests as well as to act as Fudge's spy. Although there is no indication that either Fudge or Umbridge is a Death Eater or even a Voldemort sympathizer, they likely share a paranoid belief that Dumbledore may be formulating some sinister anti-Ministry plot. It certainly appears that her job is to prevent students from learning proper defensive magic, though she may also have her own agenda for Hogwarts. She and Harry immediately clash over how the class should be taught and the Ministry's stance that Cedric Diggory's death was a "tragic accident." Umbridge's claims regarding Diggory are laughable, but demonstrates how far the Ministry will go to discredit Harry and Dumbledore and to protect the Ministry.
Although this is Fred and George's final year, there is little left for them to learn. Despite their poor academic achievements, they are extremely powerful, talented, and resourceful wizards who, much like Harry, learn best independently, in an unstructured environment and for their own interest. Readers should remember that Harry donated his Triwizard winnings to them to finance their joke shop enterprise, and the Twins have hardly been idle. They now have the necessary funding, have developed the magic, and produced the products; now they are only biding their time until school ends and they can open their own shop in Diagon Alley.
A few other noteworthy events occur in this chapter. Harry is reminded of Hagrid's absence, and once again wonders exactly what mission Dumbledore assigned him and Madame Maxime. Snape's ongoing hatred of Harry is evident. It is particularly interesting that his written instructions Harry misses seem deliberately confusing. We also observe Professor Umbridge's horrible teaching style, her useless planned curriculum, and her particular hatred toward Harry and Hermione. And now Cho, who wants to talk to Harry, is being as ill-served by Harry's friends as Harry was by the convoys of giggling girls that constantly surrounded Cho whenever Harry attempted to invite her to the previous year's Yule Ball.
- Why does Hermione believe that Professor Dumbledore wants to avoid drawing attention to Hagrid's absence?
- How does the "Ministry approved" course of defensive arts compare to how former classes were taught? Why has it been changed?
- Why does the Ministry claim Cedric Diggory's death was "an accident"?
Further Study 
- Why is the Ministry of Magic preventing students from learning defensive spells? Is this actually possible?
- Should Harry have spoken out in class? How else could he have handled the situation?
- What does Professor McGonagall mean when she asks Harry, "Do you really think this is about truth or lies? It's about keeping your head down and your temper under control!"
- Why does Harry ignore McGonagall's advice, and what will likely result from that? What could Harry have done instead?
Greater Picture 
Both Fudge and Umbridge believe that Dumbledore is using students to build a secret wizard army to take over the Ministry of Magic. Unfortunately, for now, Harry is unable or unwilling to accept McGonagall's advice to remain quiet, and he instead provokes Umbridge, earning him detention and giving her fodder for imposing even stricter rules on Hogwarts. Harry, however, has yet to realize just how severe his punishment will be and how evil Umbridge likely is.
We should mention that dissatisfaction with Umbridge's teaching is becoming widespread. Hermione will later suggest that Harry secretly teach a more practical Defence course; though Harry only reluctantly agrees and is expecting very few students, the resulting organization, much to Harry's initial surprise and dismay, will attract some twenty-five or more students. This organization, called Dumbledore's Army, being a rebellion against Umbridge, and by extension the Ministry, will, at times, be Harry's one cheering influence in what could arguably be his worst year at Hogwarts.
While we only see Umbridge in Harry's class, we soon learned she also teaches other Defensive Arts classes. Fred and George, in year 7, apparently are in her class, as they had earlier asked "who had assigned the Slinkhard book" for the course. And later, their classmate Lee Jordan gets into trouble in her class and serves detention. This also allows some speculation on exactly which courses Fred and George managed to receive decent OWL marks. In the previous year, the first after the Twins' OWL results were available, the Defence Against the Dark Arts instructor was the false Professor Moody. Moody was clearly a stern, though fair, teacher, and as such he would have probably required at least Exceeds Expectations at OWL-level before he accepting a student into NEWT-level Defence Against the Dark Arts, all the more so as he was likely to be training them in more dangerous jinxes and curses. We can guess, then, that the Twins must have managed to achieve Exceeds Expectations in Defence Against the Dark Arts, this being one of their three passable OWL marks apiece.