A/N: I'm posting this chapter in part in celebration and thanks after my main story, Umino Iruka and the Will of Fire, hit 100 Favorites. Thank you so much to everybody supporting me in my journey as a writer.
Anyway, to be honest, most of this chapter is setup. The rant at the end by the unnamed blood-purist Wizengamot member is the real point of this idea. Everything else is just a way for the exact events of the graveyard to become known. More info below.
"Can't I just take Veritaserum or something?" Harry's question caused the murmurs in Courtroom Ten to lull, for a moment. Even the Headmaster was looking at him in surprise. "Or maybe I could show my memories in a Penseive? You keep saying I'm lying, and if I am then wouldn't that prove it to everyone?"
The Umbridge witch took on a saccharine smile. "That would be the case, except that all Veritaserum could show is that you thought you were telling the truth. We've all already heard ample evidence that your grasp on reality may not be as firm as you would have us believe. As for a Penseive, the memories could easily be altered or entirely fabricated. In both cases, you are talking about using valuable and expensive Ministry resources just to show everyone what we already know - that you are nothing but an attention-seeking liar!"
"Dolores!" Madam Bones's harsh rebuke cut across the toad-woman's words. "I find it highly suspect that, on top of the procedural irregularities of this 'trial', you and the Minister seem to have decided upon a verdict and sentence in advance. If you're correct and Mister Potter is indeed lying, then you lose nothing by proving it. In fact, your insistent attempts to pass judgment without hearing evidence lead me to question precisely what it is about this evidence so frightens you."
"If you're worried about the memories being faked, somehow," Harry stated, starting to draw confidence from having somebody speaking against the behavior of this borderline kangaroo court, "couldn't you use the Veritaserum to confirm that the memories are accurate? Since one or the other alone isn't enough, use them to confirm each other. I'll even pay the Ministry back for the costs of the potion, whatever the usual price is for a dose, so there's no chance of me wasting expensive potion that the Ministry paid for."
"And before anyone attempts to further question the veracity of memories shown in a Penseive," Dumbledore was speaking now, though still refusing to meet Harry's eyes, "memories which have been falsified, altered, or are the result of dreaming or delusion are readily distinguishable to an experienced viewer. Given recent aspersions cast upon my own character, I invite you to confirm my assertions with your own experts."
Both the Wizengamot and the gallery erupted into muttering with the occasional shout, while the Minister and those around him appeared to be in an increasingly heated discussion behind some kind of silencing spell. Finally, after several minutes, the three appeared to reach a decision which left the Minister looking awkward and his Senior Undersecretary fuming. Percy was scribbling furiously at his station, before drawing his wand, casting the spells necessary to see a sheet of parchment rising from his desk and fold itself into an airplane that flew out through the doors that had just been opened slightly by one of the Aurors present.
Several minutes passed in tense not-quite-silence, before the doors to Courtroom Ten opened once more, admitting first a hovering waist-height pedestal, followed by an Auror that was apparently levitating it with his wand, followed by a second person in an all-concealing hooded gray robe. This second person was carrying a broad stone bowl that Harry could only assume was a Penseive like the Headmaster's. The Auror set the pedestal on the floor in front of Harry, and the man/woman/animated robe behind him set the Penseive on the pedestal.
After the mysterious figure in the gray robes (who introduced themself as an "Unspeakable" and who Harry still couldn't even make out a gender) explained the process to Harry, they proceeded to extract copies of his memories of the Dementor attack, the Third Task and its aftermath, the encounter in the Shrieking Shack, and several other incidents. Each strand was placed in a separate phial and labeled with a number. The effects of the Veritaserum would leave Harry unable to focus clearly enough to give his memories, so they had to pull anything and everything that might be asked about before Harry was dosed or be forced to wait until after the serum wore off to extract the further memories and then dose him a second time, all of which could take hours and would use up a second dose of the rather expensive truth serum. At first Harry had just given the three memories he most wanted seen, but then it occurred to him that other questions might be asked, and he just kept thinking of more memories that might turn out to be needed.
Finally, once all of the memories were ready, the Auror stepped forward. He, the Unspeakable, and the Headmaster each confirmed the Veritaserum for what it was, and Harry officially gave his consent to be dosed. Three drops later, he felt a calm relaxation come over him; it wasn't entirely unlike the Imperius Curse, and he suspected he could probably at least resist it if he had to, but he wanted to tell the truth, so he just went along with it.
Once it had been confirmed that Harry was fully under the effects of Veritaserum and the required opening questions had been asked to confirm his identity, Umbridge was the first to speak. "Now, did you or did you not cast magic in a Muggle area, in the presence and full view of a Muggle?"
"I did. I used a Lumos spell to find my wand then a Patronus to drive away the Dementors that were attacking us." It felt like the words were just spilling out of him, coming too fast and slippery for him to do anything but speak his answer immediately.
Umbridge scowled. "You cast a light spell to find your wand? Did you somehow lose track of your hand, perhaps?" Her sarcasm was practically tangible in her second question.
"I was desperate. Dudley punched me, and made me drop my wand. It was too dark to see, so I tried to cast the spell, and my wand lit up where it was lying on the ground."
Many people present in the chamber blinked at that, including Dumbledore. Casting magic through a wand you weren't even holding wasn't exactly business as usual. Wanting to move things along before Umbridge could derail them any further, Madam Bones asked, "Does one of the phials contain an accurate copy of your memory of that incident, and if so which one?"
Harry stated which phial contained the requested memory, and everyone watched as the scene was projected above the Penseive, starting from when Harry had first felt the Dementors approaching to Mrs. Figg's arrival. Once the memory finished, and the Unspeakable confirmed that there were no signs of tampering or delusion, Harry detachedly looked up at the three judges: Madam Bones looked to be thinking about something, and whatever it was clearly didn't make her happy; Minister Fudge was looking slightly green, and as if he would really prefer to find out that none of what was happening was actually real; Umbridge was glaring hatefully at Harry, with an intensity he'd only ever seen on Snape previously.
"Auror Dawlish," Madam Bones called out to one of the Aurors in the room, "I want a full census done of the Dementors at Azkaban. If there are a pair of Dementors out there attacking people, we need to know if they are new, if they escaped Ministry control somehow, or if somebody sent them. Speak with Amos Diggory as well, maybe his department can help."
Seeming to recover a bit, Fudge got a calculating gleam in his eye. "Another matter needs to be resolved, Amelia, for everyone's sake I believe. Mister Potter, which of the phials, if any, contains your memory of the events during and after the Third Task of the most recent Triwizard Tournament?" If he couldn't get the Potter boy expelled over his underage magic use, he'd turn this whole ploy against him and prove once and for all that Lord Thingy was dead and gone and that Potter was either lying or insane.
Harry indicated the requested memory, and it was soon being projected for everyone to view. They watched:
"Let's just take it together."
"Kill the spare."
"You stand, Harry Potter, upon the remains of my late father. A Muggle and a fool..."
"He's back. Voldemort."
"My master's plan worked. He is returned to power and I will be honored by him beyond the dreams of wizards."
The memory ended, and the chamber was utterly silent save for a couple of witches and wizards softly weeping and the Unspeakable quietly affirming that no part of the memory showed signs of falsity. After almost a minute of stunned stillness, a rustling of robes announced one of the Wizengamot members standing from his seat.
"That memory..." he began, sounding nearly overcome with emotion, "That memory has left me incensed almost beyond words. We just witnessed as that... creature that openly admitted to having been a half-blood wizard ordering the murder of a Pureblood student. And what quarrel did he have with young DIggory? None! 'Kill the spare,' he says, ordering the death of a young Pureblood wizard as dismissively as ordering dinner. The boy was not his enemy, nor truly an obstacle; a moment's thought produces numerous ways in which he could have been used as an asset, and yet that creature orders him disposed of! This, to me, forever belies any claim the Dark Lord ever made about being a champion to Purebloods!"
"You all know me," he continued, "and you know my beliefs. I have no love for Muggles, nor for the disruption of our society and destruction of our traditions their magical children bring. I firmly believe that Muggleborns and their families are the greatest risk by far to the Statute of Secrecy. I have been known to use such impolitic words as 'mudblood' and 'blood-traitor' in more candid conversations. None can accuse me of being pro-Muggle."
"However!" Now his voice rose, passionate and angry. "I say now that neither the Dark Lord nor his followers are champions of the Pureblood cause. These witches and wizards, all or nearly all of them Purebloods, debase themselves before that abomination that was once a half-blood, kissing the hem of its robes. They allow it to torture their fellow Purebloods. At its behest, they did and likely will again set out to murder their fellow Purebloods solely for the 'crime' of refusing to bow before their half-blood master. I say to you now, that they, the Death Eaters, are the true blood-traitors!" At that, the chamber erupted.
A/N: There's the real core of the idea. Seeing the fact that Voldie is a half-blood that has Purebloods killed for not following him, those blood purists not already fully committed to his cause deem him and his followers to be the biggest threat to Purebloods in Britain, and decide that Death Eaters are far greater blood-traitors than Muggle-lovers like Arthur Weasley. From here, I would take things in a direction where Riddle and his buddies suddenly find themselves with a lot less support than they had last time around, and in fact now have both the progressives and the conservatives in the Ministry and Wizengamot viewing them as enemies.