If the SCOTUS Justices Were Characters in Harry Potter....

1.  JUSTICE SCALIA IS DOLORES UMBRIDGE 

Let the battle of the sassy conservatives begin

Truly a match made in originalist heaven.  They both love rules, hate change, and are sticklers for doing things "by the book" (or, in Scalia's case, "by the original intent").  Reading a Scalia dissent is like sitting through an Umbridge detention, but instead of writing "I must not tell lies" in your own blood, you would be writing "I must not breath life liberally into the Constitution." Plus, they even do the same quirky head tilt: 

"Why yes, Dolores, I do believe public policy argumentation is impractical and for sissies!"

2.  JUSTICE THOMAS IS HORACE SLUGHORN 

"This would be better in an armchair"

Like Horace Slughorn, Justice Thomas enjoys a good armchair.  Also like Horace Slughorn, Thomas prefers to sit back and watch how things occur before really forming a concrete opinion.  Only in the case of Clarence Thomas, it's less "hey, should we kill these mudblood spies?" and more "hey, should we overrule Proposition 8?" 

3. JUSTICE GINSBURG IS MINERVA MCGONAGALL

Oh my GOD they're adorable

Look at Justice Ginsburg. Just look at her:

"We have neither desire, need, nor right to know most of Judge Roberts's views on most imaginable subjects."
 --RBG

Now look at this excellent picture of Professor Minerva McGonagall:

"Do what you have to do. I'll secure the castle."
--MM

Now look at this picture Justice Ginsburg wearing McGonagall's signature pointy hat:

This is the face of magical feminist justice 

I rest my case. 

To elaborate: They are both incredibly tough feminists who rock schoolmarm hairdos and never give up when it comes to making sure justice is served. 

4.  JUSTICE KENNEDY IS ALBUS DUMBLEDORE

When the finger is raised, evil pays

Besides the obvious "yes, they are both quite old and doddery," Justice Kennedy and Dumbledore have loads in common.  Both men are considered swing voters (Dumbledore was neither conservative nor liberal; he merely went with common sense and refused to draw firm, hard lines).  Both men were appointed by people who thought that said appointment would result in favorable results which didn't really happen. 

5.  CHIEF JUSTICE ROBERTS IS RUFUS SCRIMGEOUR 

They're both bitter because RBG/MM belittle their masculinity

They both were appointed to positions of power to further a conservative agenda. Plus, both men are really, REALLY good at damage control. 

6. JUSTICE BREYER IS MAD EYE MOODY 

CONSTANT VIGILANCE!

Like Mad-Eye Moody, Justice Breyer prefers a more practical approach to things. Only, instead of advocating for teaching 13 year olds how to kill people by saying magic words, Justice Breyer advocates involving the American populace in more governmental decisions (which, when you look at it, could basically result in the exact same thing).  Also, Justice Breyer is a curmudgeony liberal reader of statutes who thinks that Congress lacks perspective.  Mad Eye Moody is a curmudgeony liberal gadfly who thinks that the Ministry of Magic lacks perspective. The only difference? Justice Breyer still has both his eyes. And has never killed anyone. Not even Scalia. 

7. JUSTICE ALITO IS DRACO MALFOY

My father/Scalia will hear about this!

He's basically considered Scalia's deputy. And if Scalia is Umbridge, then that would make Alito the horrendous butt kisser Draco Malfoy (since Draco Malfoy was actually the head of the Inquisitorial Squad).  

8.  JUSTICE SOTOMAYOR IS GINNY WEASLEY 

Feminism is beating the boys at their own game(s)

Like Ginny Weasley, Justice Sotomayor came from an impoverished background and then basically won at life by being awesome.  Also like Ginny Weasley, Sotomayor seems to piss off white men for being better than them and knowing it. Only, instead of beating all the Gryffindor boys for a spot on the Quidditch team, Justice Sotomayor pointed out the fact that her experience as a Latina woman brings a more well-rounded view to the bench.  Newt Gingrich called Justice Sotomayor "a racist." The rest of the world called Justice Sotomayor a bad-ass. 

9.  JUSTICE KAGAN IS HERMIONE GRANGER

They're smiling because they know they're ALWAYS RIGHT

Like Hermione Granger, Justice Kagan basically bested everybody at school, went on to be extremely successful and politically connected, and then went back to school (only Hermione went back to learn; Justice Kagan went back to be the Dean of Harvard Law School).  Jeffrey Rosen said Kagan has the "ability to puncture her colleagues’ bloodless abstractions and tendentious arguments, and to explain the constitutional stakes in plain language that all citizens can understand." Replace "colleagues'" with "Umbridge's" and "constitutional stakes" with "magical theory" and essentially you have the most succinct character summary for Hermione Granger (Book 5) ever. Plus, if we continue the metaphor of "Scalia is Umbridge," Rosen also said that Kagan's writing in her dissents gives Scalia "a run for his money."