We had a thread like this on the Quill for awhile (I'm not sure where it went off to, and I can't get to it at any rate), but as a writer, the question of how the Marauders functioned as a group interests me. I also came from a high school group with large segments still connected, so it interests me on a RL level as well.
First, I don't "ship" any of the Marauders in the fandom sense of the word. Just getting that out front. But the relationships among them--as a full group, in dyads within the group, whatever--are what make them interesting for me to write about.
I'm a Friend of Peter, I suppose--I believe that he has something important to do, and I feel quite sympathetic to him--but I can't quite get on the bandwagon with the "James and Sirius must have chosen him as a friend for some reason" school of thought.
Hogwarts is a boarding school with a strict and somewhat insular house system. Harry has five people in his dormitory, all the male Gryffindors of his year, as far as can be ascertained by the text. It seems to me quite likely that in the Marauders' year, there were only four in the dormitory--James, Sirius, Remus, and Peter. Unlike Harry, Sirius, at the very least, appears to be very outgoing and extraverted, and the implication of the text is that James is quite the same. Peter is shown to crave approval from such powerful people, and Remus wants to be liked. It's very unlikely that James and Sirius would have, Harry-like, allowed the other people in the room to just go about their business. They would have forged a group out of the material that they had, made it special to belong even though it started out as something arbitrary and value-less.
At first, this may have been nothing more than a run-of-the-mill group of high school friends, as likely as not to dissipate after school with the exception of chatty letters. But then, they learn a secret--Remus's lycanthropy. And they conspire to keep it and to take care of him. So now, they are four people with a shared committment and a vested interest in one another. Given group dynamics, it's probable that this was when they morphed from casual friends into an ur-family. What had been chance becomes choice.
James is too much of a question mark to make a guess at, as to his reaction to the group formation--it can be assumed that he wasn't averse to it, but that's really the only "read" I have on him--so I'll look at the others.
Given Sirius's home life (and his behavior bears this out), he's likely to have been the one who took this most passionately to heart. As Harry "adopted" the Weasleys to make up for his miserable life with the Dursleys, so Sirius "adopted" his brothers (and James's parents) to make up for life at Grimmauld Place. He might tease Peter, as we saw in the Pensieve, but if anyone else tried that, they'd have one short-tempered, quasi-unstable Marauder on their hands. I can also see him randomly buying gifts for the others, coming up with a lot of their secret codes, and so on. Each thing he did would bind the group more tightly. Over seven years, quite a feedback loop would have happened.
Remus has a great need to be liked and accepted, and the others gave him both in great measure, accepting his disease and even finding a way to help him bear it. (Even symbolically taking it on themselves, by also becoming beasts every month... though their animagus transformations aren't the same, and I wonder if Remus sometimes thought that they didn't really understand what they were accepting.) He must have been extremely grateful to be included. Given his behavior, though, it also seems that he wasn't sure it was permanent, that their acceptance could be withdrawn at any time, for any--or no--reason. (Blasphemy to Sirius, probably.) He seems to have a relatively strong personality, which he wouldn't have changed to suit them, but he doesn't have a strong will when it comes to crossing them, because he's afraid of losing them. He would also have been a favorite of the teachers--very bright, but not disruptive like James and Sirius. Unlike Percy, Remus has a strong sense of interpersonal dynamics, so he would deliberately not try to take charge within the group, or draw attention to his success with adults. (This would produce his later behavior of being pretty much at home with both students and colleagues... he's used to living in both worlds; he's just changed which one he's "officially" affiliated with.)
We're told repeatedly that Peter is drawn to people more powerful than he is, and nothing in the books so far leads me to doubt that. The other three are all powerful in different ways, and Peter was probably very excited to be counted in their number. While I doubt his Pensieve behavior was his everyday demeanor--he was nervous about his OWLs and in awe of James and Sirius for being so cool about it all--the way Sirius and James respond to him gives off a pretty strong "mascot" vibe. They are fond of him, and G-d help anyone else who messed with him... but he'd also be the one who would get their nasty streak most often. And yes, I mean "most often," even more than Snape--maybe not the spectacular stuff, but the little, almost unconcious cruelties that people inflict on one another. And because he wouldn't complain--would probably smile and laugh, unlike Remus, who really made them feel guilty from time to time--it would never even enter their minds that it was hurtful to him. (I had a friend in high school who spent four years calling me "Blarf" instead of "Barb." I knew he didn't mean anything by it, so I never said anything--why risk a big emotional confrontation over something that meant nothing?--but it really made me seethe.) So Peter would be the get-along guy... until, of course, he blew his wheels completely, and Sirius and James would be honestly puzzled by it, because, hey, he never said anything, and we'd have died for him.
In the various triads in the group (James-Remus-Peter, Sirius-Remus-Peter, James-Sirius-Remus, James-Sirius-Peter), any group of three that had only James or Sirius would be a default military unit under a commander, who thought up the ideas while the others thought up ways to make them happen. This isn't a negative--some people are natural leaders, and it looks like James and Sirius were in that category. Nor is it speaking poorly of Remus and Peter; neither would necessarily want to do those things alone, but in most cases, they probably also went along because they thought it was fun, not because they were blindly following a leader. There might be slight differences between James and Sirius in the matter of what they'd do, but the group dynamic would be the same. When they were both involved with only one of the other boys, though, the dynamic would be different.
We get to see (in retrospect) the James-Sirius-Peter dynamic in the memory of the animagus spell: James and Sirius did most of the work, and helped Peter along to follow them. It's important that they did not leave him behind or despair of him--I think it would have been unthinkable to them to leave him out. Did this carry over into adulthood, with James and Sirius working on the Fidelius charm, and Peter along essentially by habit, with Sirius's brilliant switch idea happening at the end of some bull session? I think it's possible. After all, it was this triad, not James-Sirius-Remus, that had already formed a conspiracy. (And it's probable that Peter rather skillfully led the conversation in this direction.)
James-Sirius-Remus would have a slightly different feel, because for the most part, Remus seems to have been more respected--he wasn't the little one who needed tutoring to go along with them, and he was the one that the others had conspired to protect. I have a feeling that this particular triad happened mainly when James and Sirius crossed a line and went too far with someone else (eg, Snape)--Peter, not wanting to be involved, would withdraw. Sirius said that Remus made them feel guilty from time to time, so I have a feeling that this triad could be somewhat uncomfortable: Remus, who doesn't face them down in public, dressing them down in private, hitting all of their emotional weak spots (as he does with Harry following the Hogsmeade visit). "Sirius, your mother would be proud of you today" or "James, yes--twenty generations of Potters are smiling on you now, aren't they?" Not that they wouldn't have fun with Remus as well, but I get the sense that when Peter was out of the picture, it was because they weren't in the process of having a good time.
There would be six different dyads in the group--James-Sirius, James-Remus, James-Peter, Sirius-Remus, Sirius-Peter, and Remus-Peter.
Everyone in the books agrees that the most visible and closest dyad was James-Sirius, and Sirius's behavior in OotP bears this out. They appear to have been like the Weasley twins to a lot of people--basically, two people functioning as a single entity. But the way Sirius talks leads me to believe that there was a fairly large inequality between them, at least as far as their needs went. Obviously, James loved and accepted Sirius. But, as with Harry needing Ron, Sirius needed James more than James needed Sirius. It is James who has the power to open his home to the unhappy Sirius, and James whose "cleaner" family could offer acceptance to the son of an enemy. There's no evidence that James got (or wanted) anything equivalent from the relationship--he gave, and Sirius gratefully received. What he was able to give in return was his total and eternal loyalty. That said, like Ron, it didn't look like James thought he was the one with the power. The dynamic Sirius, like the chosen-by-destiny Harry, would seem to automatically hold some sort of power in a friendship, so James sees him as an equal.
For James-Remus and James-Peter, again, the unknown parts of James's character make it hard to guess. Obviously, Peter hero-worshipped him more than Sirius (just judging from the Pensieve), and he didn't mind it, but that's about all we can guess. Remus doesn't talk that much about his friends individually (more as a group--a pack, if you like), so without the other half of the dyad, it's hard to tell what that might be like.
Although I think of Peter and Remus as being the same "level" in the full group--the warriors for the chiefs to assign--the Shrieking Shack scene suggests that Peter also sought Remus's approval, and that Remus felt much more free to be... well, Remus. In the Shrieking Shack, it's Remus who sits there making the logical arguments with Peter for pages, while Sirius interrupts frequently with emotionally charged outbursts. Now, this is obviously not the best time to see Peter, but extrapolating out from it, you could see him in the dormitory, maybe having trouble with is homework or having some burning question, and Remus taking the mantle of authority to counsel him. Because Peter is as craving of acceptance as Remus is, there's less a "threat" of him withdrawing his friendship if Remus behaves authoritatively (which appears to be his natural inclination).
(Poor Peter--he's just a regular Joe, and with other regular Joes, he might have done just fine.)
Sirius-Remus. This is the only one of the dyads we see in adulthood, and I have a feeling that it's shifted slightly due to Sirius's increasing instability--Lupin in OotP seems to have taken on a caretaker role that I doubt he had at Hogwarts. (In fact, he's probably subtly taken on some of James's authority.) But--at the risk of angering R/S shippers--I have to say that it doesn't seem to be a particularly strong dyad within the group. Sirius is probably a ringleader in being protective or Remus--Sirius seems to want to be the defender of people he deems in need of defense--and Remus is grateful for that, but again, Remus seems to look at his three friends as his pack, all equal to one another in one way or another. And Sirius's primary attachment is to James, with the other two as younger brothers. (If I were to make them into actual brothers, I think I'd make their birth order James, Sirius, Remus, Peter, just by the way the group behaves about authority.) For their specific dyad, it looks like Remus functioned--or tried to function--as Sirius's conscience, while Sirius and James, as a pair, got Remus out of his natural complacence.
Anyway... thoughts on the Marauders.
EDIT: Cross-posting to hp_essays