Cornelius Fudge uses this opportunity to appoint Dolores Jane Umbridge as the Defense Against the Dark Arts teacher at Hogwarts when Albus Dumbledore is not able to find another person to do the job.
Dolores Jane Umbridge was appointed High Inquisitor in order to give the ministry more authority at Hogwarts School of Witchcraft & Wizardry. She is given the power to inspect her fellow teachers and fire any that she believes are not up to scratch.
Professor Umbridge posts this Educational Decree when she finds out about a secret Defense Against the Dark Arts group being formed by Harry Potter and his friends. Willy Widdershins notified Umbridge of this group after he witnessed a meeting in the Hog's Head pub. Obviously, Harry and the rest of the group had no intention of asking Umbridge to reform, and carried on with their meetings illegally. Some were surprised that this Decree included Quidditch, and naturally Umbridge was delighted at holding the Gryffindor Quidditch team's future in her hands. Eventually Dumbledore, who still had higher authority at this point, forced her to let them re-form.
Professor Umbridge used this Decree to give Harry Potter, Fred Weasley, and George Weasley a lifetime Quidditch ban after attacking Malfoy on the Quidditch pitch. Professor McGonagall had only been intending to give them each a week's detention, but Professor Umbridge now has higher authority than any staff member, and even Dumbledore himself. This ban is even more unfair when you consider that Fred Weasley never even attacked Malfoy, but was banned because his twin did.
Somehow, Umbridge must have found out about Professor Snape giving Harry Potter Occlumency lessons, since this seems to directly target them. This also prohibits any Professors who are in the Order of the Phoenix from giving students like Harry Potter, Hermione, or the Weasleys, any information about what's going on with Lord Voldemort.
This Decree was placed in order to stop students from reading Harry's interview in The Quibbler about the night Voldemort returned. Umbridge also retaliated against Harry by banning him from Hogsmeade and giving him more detentions. Unfortunately for Umbridge, banning the magazine made it even more popular among students. They found all sorts of ways to disguise the magazine in case Umbridge ordered them to turn out their pockets.
After Dumbledore's escape from right under the Cornelius Fudge's nose, Umbridge became the Headmistress. This is especially unfair as Minerva McGonagall is Deputy Headmistress, and should have taken over for Dumbledore when he escaped.