Getty Images/Chip Somodevilla

Sen. Dianne Feinstein, pictured May 13, 2009

Updated Nov. 28, 2011, 4:54 p.m.

Sen. Dianne Feinstein has a challenger in the 2012 election.

Elizabeth Emken, a children's advocate from Danville who lost a congressional bid in 2010, announced her candidacy Monday on Flashreport.org, the conservative blog covering California politics.

According to her bio, Emken, 48, has plied the legislative corridors for 20 years as an advocate for children with autism. (She has a 19-year old autistic son.)

Emken lost a primary battle against David Harmer, who went on to unsuccessfully challenge incumbent Democrat Jerry McNerney for California's 11th Congressional seat, a swing district that straddles the wealthier, hilly parts of the East Bay and the Central Valley.

So with the election a year away, how does the horse race look?

For starters, Republicans think Feinstein is vulnerable, and have been scrambling for weeks to find somebody -- anybody -- to challenge her. The name of Orly Taitz, a dentist from Orange County (where else?) who played a leading role in the "birther" movement, has been bandied around, but most Republican operatives dismiss her as a non-starter.

Whoever wins the GOP nomination will go up against Feinstein at a time when she's at a personal low in the approval polls. Still, handicappers for 20 years have consistently described Barbara Boxer, the liberal Marin-ite, as the more vulnerable of the state's two senators and she handily beat former HP CEO Carly Fiorina in 2010. So Emken -- or whoever -- will probably have to mount a tremendous effort to get close to touching Feinstein.

But what might throw a little twist into the race is the fact that the senator lost almost $5 million in an embezzlement scandal involving her campaign treasurer this year.

Correction: A previous version of this blog incorrectly stated that Emken was endorsed by Sarah Palin in 2010.