Joshua Michael Stern’s Swing Vote looks like the kind of “familiar” that could find a very large audience.

If the hook – an unemployed single-father is saddled with the deciding vote in a U.S. presidential election – sounds sounds too irresistibly Capra-esque to be completely original… well, it isn’t: Garson Kanin and John Twist used a very similar premise for their unheralded (and currently unavailable on DVD) The Great Man Votes in 1939. That said, it’s the kind of idea that two writers could conceive of independently (and nearly seventy years apart), so let’s not go alleging plagiarism just yet. No, let’s wait until the film is a sleeper hit in August before we start tearing it down for ripping off a “classic” most of us have never seen (though, as a fan of Kanin’s writing, I sure would love to see it at some point).

The trailer is slow-pitched straight down the middle, which means it’s assembly-line fluff decked out with “dead” music cues (a man confronted with a decision that will determine the fate of nation must be… “Under Pressure”!). And yet it looks eminently watchable thanks to Costner’s ever-affable presence. The young girl may be a little Breslin-y, but the rest of the supporting cast is aces (Stanley Tucci, Nathan Lane, Dennis Hopper, Kelsey Grammer, etc.). If done right (and not necessarily well), Swing Vote could capitalize on Election ’08 fever and play well into October.

We’ll find out August 1st.