Identity politics usually gets portrayed as something transactional. Some group wants something, and you give it to them in exchange for their support. It could be appointing one of them to an office, or supporting their position on some issue.
I wonder if something bigger than that is possible in the case of the Hispanic community. As far as I can tell, the Hispanic political identity is still somewhat malleable, and there's much to be gained in shaping it. One way to do this is to raise the profile of Hispanic left-wing figures, and get them into fights with unappealing non-Hispanic Republicans. It's true of everybody -- if you don't have strong feelings on some issue, but someone you regard as one of your people presents articulate and forceful arguments on that issue, you're going to gravitate towards the position she was arguing for. It works especially well if she's arguing against some obnoxious outsider.
I don't know if Sotomayor is the right person to pull this off, just because I don't know her well enough. But if she's good at dealing with confirmation hearings and then does a good job on the bench, and if liberals can generally do a good job in the media war around her, she could become the sort of figure who makes progressivism and the Democratic Party more attractive to Hispanics.
(I don't know to what sense Hispanics with roots in different Spanish-speaking countries see themselves as members of the same political community. In any event, if we're talking about constructing a certain sort of political identity rather than transacting with an existing one, this is the sort of thing we're trying to shape.)