The difference between the parties right now, in a nutshell? You all know all about Ted Cruz in Texas, and you probably know about Todd Akin in Missouri…but odds are that you don’t know anything about Mazie Hirono and Ed Case.

Hirono and Case are the Democrats competing for a Senate nomination in solidly Democratic Hawaii; while Republicans have recruited their best possible candidate, it’s still much more likely than not that either Hirono or Case will be the next Senator from Hawaii. And given that state’s reluctance to boot anyone, it’s not all that unlikely that the winner will serve several terms, even though neither is young. Hirono has been thought to have the edge; Political Wire today has two polls that show mixed results.

And yet, despite a clear issue split between them, with Case more moderate and Hirono more liberal, there’s been little talk of this contest that I can see. Not none — you’ll find some postings over at Daily Kos, for example. But certainly not what we saw in the Texas Republican primary, or in Richard Mourdock’s upset of Dick Lugar in Indiana.

Now, whether potentially risky conservative challenges such as the one that yielded an Akin win yesterday are smart strategy is a complicated question, but this one is an easy call: Liberals almost certainly would be better off with Hirono. And, again, there is a some activity there. But it sure doesn’t catch the imagination of liberals the way that similar challenges receive intense interest from conservatives. I’m not sure that I have an explanation for all of this, but I do think that anyone who wants to understand Congress needs to be aware of it.