The dilemma of Richard III comes into clearer focus as you get deeper into this story.  As Baraou no Souretsu tells it at least, Richard is loyal to what he sees as the legitimate monarch.  He may even love his brothers on some level.  But he’s also struck with the reality that he’d make a much better king than either of his brothers – one “lacking the awareness of a king”, the other “unqualified to be king”.  Richard may have mommy issues and a lot of self-loathing, but he knows he was the one in his generation that got the brains.

At the moment it’s Warwick who’s the one pulling the strings.  A role which he considers his natural habitat and birthright, to be sure.  He’s decided he cannot forgive Edward for humiliating him with the French monarchy, but his first plan has gone ass over teakettle with Richard overhearing what he wasn’t supposed to.  He travels to France to win Margaret of Anjou over to his side with a promise (which I don’t think he ever intended to keep) to restore Henry to the throne.  But George seems to be the horse he’s still backing.  Margaret insists on proof of Warwick’s sincerity – to wit marrying Anne off to her son Edward (of Westminster, who’s also in love with Richard, naturally).

After Edward (York) forbids George from marrying Isabelle Neville, it’s a fait accompli that the middle brother will betray the eldest.  Secret marriages must run in the family, as George weds Isabelle without the king’s permission.  Warwick foments a rebellion, which Edward (York) refuses to believe him capable of despite Richard’s warnings.  That poor judgment leads to him being captured by the rebel army and taken to Warwick’s castle, and soon Warwick and George are marching on Edward (York’s) castle in order to take Elizabeth and Richard prisoner.

Warwick’s wannabe successor as master manipular Henry Stafford correctly sees this as an opportunity to destabilize the kingdom enough to nudge Richard closer to the throne.  But Richard isn’t willing to make that leap yet himself.  He thinks about it, he knows in his heart he should claim the throne for himself, but he decides for the nonce to come to Edward (York’s) aid.  It’s only the ever-loyal Catesby leaving his own lord’s side and coming back to look for him that allows Richard to escape Warwick’s clutches.  As for Edward (Westminster) he seems primarily interested in kissing Richard again, which is a good thing because apart from his mother no one seems interested in seeing him ascend to the throne.

While Richard is holding himself back seemingly to assuage his own conscience, it probably makes sense strategically for him to let Edward (York’s) foolishness cause his downfall rather than be the one to engineer it himself.  Having stood loyally by the old king will look better to a lot of people than having plotted to usurp him (as George did).  The flaw in that reasoning, of course, is that if Edward (York) screws things up badly enough, there may not be much of a kingdom left to inherit.  Of such unpleasant conundrums is the historical story of Richard’s life written.