Note: This post has been automatically imported from my old blog. Formatting may be incorrect.
EDIT 1/24/13: After seeing the movie, I now agree with Rory's interpretation in the comments (that Javert's obsession doesn't start until after the confrontation). This post left up for posterity.
In response to the long twitter thread started by this tweet, I wanted to explain why Javert's obsession with Valjean (in the musical) strikes me as a bit strange.
From the musical, what Javert knows about Valjean is that he "stole a loaf of bread", "broke a window pane", "tried to run", and then failed to report for his parole (from having read the beginning of the book, I know that "tried to run" means "tried to break out of prison", but that's not in the show). The show does an amazingly compelling job of showing why Javert despises Valjean: Those who falter and those who fall must pay the price, men like you can never change. Those central precepts guide Javert's path through the show, and the contradiction between them and Valjean's choice to save his life at the barricades ultimately invalidates his entire conception of the world (rooted, ultimately, in his desire to separate himself from the gutter from which he came by crushing it under his feet). This is beautifully and powerfully presented in the show, and easily overcomes the flaw in the story to make Javert and his theme of justice one of my favorite aspects of the show.
But there's that damn little flaw. Javert's obsession with justice makes sense. Javert's hatred of Valjean makes sense. But Javert's obsession with Valjean doesn't. Why is Valjean special to Javert? Surely there are worse criminals, others who have broken their parole? Javert hates Valjean, sure, but the Javert presented in the show would hate any criminal, especially any criminal that escapes (nay, mocks) the law. Given all of the criminals he must have come into contact with, why spend so much energy on Valjean? A few people in the original thread compared Valjean to Ahab in Moby Dick, but while Valjean may share Ahab's obsessiveness he doesn't have Ahab's excuse that Valjean was the only whale to take his leg.
Ultimately, I find it easy to look past this and really enjoy the show (and look forward to seeing the movie next week). But I think it would have been fairly easy to fix the problem, so I think it's a shame that the show is as it is. Off the top of my head, I can think of three reasons why Javert might be obsessed with Valjean, and corresponding ways to show them: