Late-breaking House races shift political playing field

By Stuart Rothenberg

WASHINGTON (CNN) -- Every election cycle, a handful of races not taken very seriously early on become truly competitive contests, and this year is no exception.

Every candidate, of course, has a scenario. But most of those scenarios -- and most of those candidates -- evaporate well before October.

In the case of the candidates below, their scenarios are now supported by both polling and successful fundraising. Given the national political environment, it isn't surprising that most of the late surprises are in Republican-held seats. Read the rest of the story on CNN.com.