Well, having the head of DMLE under your control would no doubt be a huge step in the right direction of taking control, if only by providing you with access to everyone else.

In terms of other departments (some of these may be sub departments, we've no way of being sure), you've got Magical Accidents and Catastrophes, Magical Transportation, International Magical Cooperation, Magical Games and Sports, Mysteries, Regulation and Control of Magical Creatures, Central, Magical Education, Magical Equipment Control, and Administrative Regulation.

Of these, there are a few comments that can be made.

International Magical Cooperation is seen as a significant step down in prestige, a place important people get put if they've fucked up or lost a lot of influence (see Barty Crouch). Thus, I would think it isn't a department you'd need to have on side before a coup.

Magical Games and Sports is unlikely to be given much precedence, they had Ludo Bagman in charge, so its not going to be a department you need to worry about before carrying out a coup.

Magical Accidents and Catastrophes seems to be quite a prestigious department. Fudge went from a Junior Minister there to being the Minister for Magic. I think you'd probably want control of this department in the event of a coup, to ensure continuity of secrecy. No telling if a coup will cause trouble to spread out into the muggle world, and you would want control of the people responsible for clearing it up.

Central Department is seemingly analogous to the Cabinet Office in the UK. They seem to be responsible for the internal running of the Ministry. This might potentially come with physical control over the Ministry building, which would no doubt be rather useful in the event of a coup.

Magical Transportation would be vital, since we know they can monitor and control usage of the floo network. Limiting movement is always one of the first steps in taking control.

So if the structure of magical government is something similar to the UK muggle government (which seems likely given JKR's influences) then if you have the heads of DMLE, Magical Accidents and Catastrophes, Central Department, and Magical Transportation under your control then you've got a significant portion of the Cabinet under your control. And given how politics works, you're likely to see others siding with the people you control, since the nature of their positions is one of significant power.

Hell, even if you can't get control of the Heads of Department, having control over some of the sub department heads or simply well placed individuals would give you significant influence within the Ministry, and possibly accomplish as much, if not more, than controlling the Head of Department.

But certainly those are the Deparments I would target. Magical Law Enforcement, Magical Accidents and Catastrophes, Central Department, and Magical Transportation. After you've got them, everyone else should fall into line.

 

Pretty much what Mordecai said, though is needs to be said that we don't know much. We were only told that Thicknesse was under Imperius, but we can't rule out that DE plants were in charge (or in position to take charge) of some other vital Departments the moment the coup was executed. And considering the widespread propaganda that was implemented concerning the Order and muggleborns, the pureblood leadership of DE could have blamed any violence on the Undesirables.

Also, my impression is that Voldemort didn't waltz in to openly take charge, at least not at first and perhaps he remained the unofficial dictator out of public view. I think that people - well, those likely to change opinions if persuaded by propaganda - had to be eased into the idea of Voldemort ruling gradually. Until the coup, DE and Voldemort were still the bad guys.

 

Canonically speaking, it seems to be all about having the Minister. Not controlling the Minister means you don't have the Ministry; controlling the Minister gives you control of the Ministry regardless of other individuals.

We can see this in Voldemort's plan: having the head of DMLE wasn't enough; Thicknesse was just a route to the Minister - Voldemort said that he needed Scrimgeour surrounded by his own people when he went to take the Ministry. And the moment he did kill the Minister and put his own man in place, he had effectively complete control of the Ministry and was able to reverse Ministry policy 180° overnight.

We can also see in OotP why such a thing is possible, with Fudge's massive political power.

Like Muggle UK, magical UK looks to be effectively an elected dictatorship.

Of course, having such a simple route to success may be boring for fanfic purposes.

 

It seemed to have been implied that with Thicknesse giving in, others began to be converted rapidly. Or that sympathizers and those who would resist the least began to be shuffled around where they needed to be. From what I gather about the Imperius curse, it can both be used for more direct control and used for such control as to leave the victim's operational capacity intact while having powerful compulsions to go about certain courses of action.

Yaxley, through Thicknesse, may have also argued that the Blood Wards were completed or done through Dumbledore's spellwork, and as such, reliance upon the dead wizard would be shoddy. It's incorrect, but even that hint of doubt means that they may be thinking of people flooing into Privet Drive and performing an assasination attempt.

So possibly Thicknesse' subordinates being used quite effectively, or Thicknesse himself converting other members around Scrimgeour through Imperius-Chaining, which we know is accomplishable from Draco commanding Rosmerta into Imperius'ing a girl into carrying a back to Dumbledore. It did seem to be suggested that once Thicknesse fell to the Imperius, it allowed rapid conversion of others who surrounded Scrimgeour.

My guess is, Thicknesse fell under the Imperius, he began using such on his immediate peers, and using his own office to cloud the efforts of tracking Dark movements, and ensuring certain other Death Eaters and sympathizers were in key positions. By the time Scrimgeour knew anything was going on, most of his cabinet was converted and arraigned against him, one way or another, and then everything collapsed, suddenly and instantly.

If Scrimgeour hadn't been surrounded, he may have made a fight over it, and then pulled the rug out of the authority of those converted. Basically, Voldemort needed a man in the upper echelons of governance, the actual levers of power and those with access to the Minister. Once he got Thicknesse, he could then quickly convert others, already have his effective governors in place, and so he didn't have to fight a civil war after an assassination, instead, the Minister was taken out, and the entire ministry had quickly seen certain people in key positions to make the turnover instant, such as controlling where certain Aurors would be, where certain other department heads and clerks would be, and time that with the Dementors leading the way into the Ministry.

He needed people in place to make his coup stick. Instead of a civil war, people, basically, went to sleep under Scrimgeour and woke up under Thicknesse(Voldemort)with barely a hitch in normal day to day government operation, instantly handing over all of the power and functions of the Ministry to Voldemort, and not giving Aurors a chance to fight and other a chance to disrupt.

 

Hah. Give it enough time, and you could literally take over the country with one spell.

 

Chinese Whispers etc etc. I assume that there are some limits into how many chainlinks there can be, but who knows how many a Wizard can have under their control at once. Two different things.

 

Or we assume that the Order didn't know and Voldemort knew what the fuck he was doing. I think the Order would totally share information if they knew about Thicknesse and Scrimgeour seems like a doer to me, considering he used to be the top Auror.

 

Well, by gone over, they could suspect that something is amiss, but not be sure. And I don't think the Order of the Phoenix is considered particularly legitimate or a credible source by those in government.

Reading the early pages, the discussion with Snape, Yaxley and Voldemort at Malfoy manner makes allusions to "Next Saturday". It also makes a point that Thicknesse has regular contact with all the department heads and has a fairly important position himself. So atleast a week and one day. Plus five more days. So about 13 days minimum, possibly more. So about a Fortnight to convert and turn other department heads and begin preparing them for a coup by shuffling the right people around.

Not to mention small things like even the Weasley's don't keep in contact with their Squib cousin. Even the most apparently tolerant of the Purebloods, still holds those prejudices. And remember, aside from open rebels and such, only Muggleborns were explicitly persecuted. So most of the wizarding population aren't under direct threat, and with just Ministry information, Voldemort can track down his enemies almost instantly, nationwide.

Remember, he coup'd the Ministry, and that instantly gave him they power to rip away The Burrow's wards as if they weren't even there, and then put out a Taboo.

I think that's part of what prevented open rebellion. The sheer suddenness of the coup meant that by the time people put two and two together, is was far too late if they wanted to keep their families safe. That and Voldemort not explicitly taking power.

 

I think International Magical Cooperation is vital for success, as they can use it to monitor various lines of communication to other countries and prevent news of the new regime to reach magical communities abroad. I mean, with all the Muggles disappearing and the imprisonment of Muggle-borns and so forth, something tells me that had the ICW been aware what was going on... Well, if they could station an International Task Force in Tibet to manage Yetis, they could demand other member countries to contribute to another one in the name of maintaining secrecy (which the UK would be found guilty of blatantly violating) to enter Great Britain and make short work of Voldemort and his "little army". I say little because it would seem small compared to hundreds, maybe thousands of highly trained Aurors.

 

Are we talking about the "Resistance" taking over from Voldemort, or some third party filling the vacuum while people are busy dealing with the aftermath of the Battle of Hogwarts?

If it's a third party, it all depends on who they are going to have enforcing their rule. Unless they have some serious international pull to call support from overseas, I don't see how anyone else than Harry and Kingsley (supported by the remnants of the Order and the Hogwarts staff) is going to have any chance of having enough support to hold on to power, even if they somehow managed to get themselves appointed as a minister.

Of course toppling the new "legal" minister immediately after the Battle could get really ugly legally speaking, but we don't really know if the Wizarding Britain has a constitution or even proper division of power to cause real issues there. It's interesting to think, for example, what kind of process was used to send Umbridge to Azkaban for "Crimes against Muggleborns", as presumably her actions would have been perfectly legal under the Thicknesse administration.

Harry and Kingsley could probably get away with dealing justice by themselves in some sort of kangaroo court, but that would set an ugly precedent. And we don't really know how badly the Wizengamot was crippled by Voldemort; if it's only ultraconservative purebloods still alive, they would need to replace that whole body, and that would again look bad. That is, assuming they have a constitution that puts emphasis on the rule of law.

 

In this situation I think Harry is the key person. He's just very publicly beaten Voldemort and has achieved a peak level of public adoration and respect. I imagine that if anyone had tried to install themselves as Minister in the aftermath of DH, all Harry would have to do is say "I don't trust them" and the would-be Minister would have an overwhelming mob demanding their exit by the end of the day. He's basically got a veto... should he choose to use it.

Aside from Harry, the Order seems to hold all the cards in the legitimacy department. With Voldemort's regime overturned, fingers are going to be immediately pointed, and the person who can distance themselves the best from Voldemort will have the greatest moral authority. Since the Order was the only real organised opposition to the regime (and publicly recognised due to their radio broadcasts), their moral authority is the greatest in the aftermath of Voldemort's defeat. Certainty none of the incumbent political office-holders (who survived the battle of Hogwarts) stand a chance of holding onto power. The wizarding population will turn rapidly on anyone who is stained by association with Voldemort's regime.

The Order's organisation in turn also allows them to seize the initiative. It's hard to underestimate the importance of organisation/leadership in chaotic situations like this. Having a pre-existing commander in the form of Kingsley while the rump Ministry is all running around like headless chickens gives Kingsley the immediate advantage.

The only other character who it seems could even potentially contest the Order for organisation is Slughorn, who was able to muster a large contingent of wizards and witches to come to Hogwarts to join the battle. But Slughorn does not hold the ambition of political office for himself, and in any case was mostly aligned with the Order when push came to shove.

Ultimately I feel like the political situation will be resolved by essentially popular decision/the mob, not through formal constitutional mechanisms or legal powers. All people who hold legal powers at the time of Voldemort's fall are all immediately suspect in the eyes of the general populace, whereas the leaders of the resistance have the love of the people. And it's the people who ultimately matter - not just because we know that wizarding Britain is a democracy, but also because it's essentially the Wild West at this point. The government is all but collapsed, there's very few strong leaders with a structure behind them, and every citizen is heavily armed.

Re: ICW, Voldemort never broke the Statute of Secrecy, and that seems to be all the ICW really cares about. In fact it's notable that Voldemort took great care to never expose wizards to Muggles, always dressing up his attacks on Muggles as natural disasters and accidents.

 

Voldemort and his forces wreaked havoc, and it was up to the Obliviators, the Invisibility Task Force, the Muggle-Worthy Excuse Committee and the Office of Misinformation to cover it all up and come up with excuses to ensure Muggles were none the wiser. I believe Voldemort didn't openly announce the existence of wizardkind because he only held dominion over the magical community in Great Britain. Remember, he didn't move around and terrorize on a large scale like Grindelwald and his followers did, he focused on his native UK, carving it out as his own little corner of the world. Lord Voldemort might be "the most powerful and dangerous Dark wizard of all time", but he would unlikely prove unstoppable if he attracted so much international attention to himself that the ICW decided he had become a threat. Exactly because he had kept to Great Britain during his rise to power, while he was known, he had no influence or power whatsoever overseas, political or otherwise, so if the ICW decided to take him down, he would have nowhere to run and/or hide, and they would know exactly where to find him.

 

Voldemort is the same sort of problem that is seen so often in today's times. If he is killing his own countryman than it is fine, but once you kill someone else's men or women than you have crossed the line.

I have always wondered about Harry's involvement after Voldemort's fall. His public endorsement would have been all it took to raise or cast down anyone in power. The scary thing is that Harry really didn't know Kingsley, at all. They had talked, what, a few times at best? That is nowhere near enough time to get to really know someone's politics and moral code. Kingsley could have really been against Voldemort but been perfectly alright with sending people to prison over small things. It was just a lot of power to give to a person that he only knew of as fighting Voldemort and an auror. Auror doesn't scream political leader to me.

 

We know from canon that Harry is compassionate to others, and he will be your friend no matter your background. He will also help people when he has the chance ie. Dobby and Ginny. However we also have a quote where Harry admits to agreeing with Hermione about House Elf Rights when Kreature is telling him about Regulus.

That said Harry doesn't seem to go out of his way to speak against the treatment. Which leads me to believe that in the future Harry wouldn't support immoral laws however he also wouldn't speak up for moral laws unless they directly affected him.

 

Very rough, but more or less outlines it:

It certainly wasn't the future he had foreseen, but then his expertise was in Potions – and no small skill in Transfiguration – not Divination!


And in truth it had been more of a public service than anything else. After the nasty business at the school, the stark truth was that the victors were hardly more than a gang of school children with a few adult minders. Very brave and talented schoolchildren – make no mistake! - and he himself had always known that Harry Potter was destined for great things... but he wasn't ready to be the Minister of Magic quite yet!


And that didn't even begin to take into account the vast majority of the British magical population that were hardly death eaters themselves, but likewise we're less than enthused at the idea of the pendulum swinging wildly in the other direction. No, most wizards and witches wanted a peaceful, stable society, one where the next big thrill was a Sunday quidditch match and the next pleasure was a late afternoon nip of Ogden's best – not fearing from one minute if their children were going to be snatched away by werewolves and the next being told that werewolves deserved equal rights to attend Hogwarts!


He frowned at the thought. Hermione Granger was a lovely girl, truly, but far too radical and convinced of her own brilliance. He had nothing against muggleborns of course – nobody could claim as much – but the truth was that there were many who would see the likes of Ms. Granger being fast tracked through to the highest offices as much as a danger as You-Know-Who. Would she crash the potions market demanding humane treatment of dragons? Demand that wizarding society contort itself as if it were just an eccentric part of the mundane?


No, in a sensible world Ms. Granger would enjoy a slow but steady rise, culminating in a not-at-all dis-respectable place in the Department of Magical Cooperation where her talents could change society for the better... but at the right time and place.


And so, he had taken it upon himself to call in old friends and old favors. The heavy lifting sorted itself out – while the Ministry had been all but decapitated during the final battle, the reality was and always has been that the bureaucracy of Britain – magical or mundane – never really needed them. The civil service didn't stop running simply because there was nobody officially running it. And the chaps and ladies who made up the wheels of the machinery were if nothing else quick to protect their own survival. Voldemort hadn't properly cooled before the Ministry 'revolted' against their absentee masters, the Daily Prophet not far behind.


All that really needed to be done was to make sure that all the departments were tugging in the same direction. And given the choices available, they had jumped at the opportunity. After all, he was a war hero! Had dueled You-Know-Who himself! Led the rearguard into battle!


At which point, the whole thing had been laughably easy – almost anticlimactic. Shacklebolt had hinted at running for the top job himself but Harry had refused to endorse between the two of them, saying he couldn't possibly, and he himself had simply pointed out that while certainly, Shacklebolt was no doubt equally capable of doing the job, no department in the ministry was in a greater shambles than the auror corps... and wouldn't it be best if Kingsley put his rather unique talents to work there, and he himself would see to it that the Ministry and the Wizengamot gave Kingsley all the support he needed bringing any rouge death eaters to justice.


And so with near unanimous support – from purebloods and traditionalists fearing complete collapse, to muggleborns taking solace in the stories of his past and his own accomplishments at the Battle of Hogwarts, to a veritable army of quidditch stars and dueling champions and international ambassadors singing his praises from Land's End to John O'groats...


Horace Slughorn humbly accepted the position of Minister of Magic.