Cause for guarded optimism or more poll smoke? Sen. Barack Obama has apparently (a) nudged into a slight lead over Sen. Hillary Clinton in California in a Zogby-C-SPAN/ Reuters poll out today, and (b) is holding a one-point edge over Clinton in California in a 2.3 Rasmussen poll.

On top of which (c) the same Reuters poll is reporting a nationwide dead heat between the two Democratic candidates; (d) Gallup is saying the same thing; (e) ditto a CBS/N.Y. Times poll; (f) a Pew Research Center survey conducted from 1.30 to 2.2 states that 41% of registered voters have said they dislike the idea of Bill Clinton being back at 1600 Pennsylvania Avenue, if and when Sen. Hillary Clinton is elected president (with 34 percent of voters having affirmed the same view last October); and (g) Maria Shriver, the wife of California’s Republican governor, announced for Obama earlier today.