California officials have approved a rule mandating that, by 2025, 15 percent of new cars and trucks sold be powered by batteries, hydrogen fuel cells or other technology that produces little or no air pollution. California has tried this before and it didn't work.

Melissa Block talks with Sen. Jon Tester, a Montana Democrat, about his views on campaign finance laws — and, in particular, what's wrong with the Supreme Court's Citizens United decision.

Facebook is expected to file papers for an initial public offering this week, and industry watchers say the company may be valued at nearly $100 billion. Is the social networking website worth the price, or is this another Internet bubble in the making?

In the fight for Florida, Mitt Romney was able to exploit Newt Gingrich's famed lack of discipline to get the speaker to at times become speechless and to reveal a nasty streak which turns many voters off. Romney may try the same thing with President Obama but the incumbent will be a tougher target since he is famed for his discipline.

An investigation by ProPublica and NPR finds that Freddie Mac has invested billions of dollars in bets against struggling homeowners. Public records show that Freddie Mac, in a potential conflict of interest, sought to make gains when homeowners failed to qualify for refinancing.

Films such as Nanny McPhee and Mary Poppins have romanticized the nanny role, but there's no magic umbrella for the star of the reality TV show America's Supernanny. Deborah Tillman visits a home-in-crisis during each episode, helping kids and parents behave. She talks to host Michel Martin.

MacArthur 'Genius' Tiya Miles does pioneering research on the relationship between Cherokee Indians and African-Americans. She speaks with host Michel Martin about shedding light on the unexplored history of Native American and African-American slavery in Michigan.

Carol Sikler has spent years repaying a debt. Her husband needed blood during treatment before he died in 2003. Since then, she has donated more than 140 units. Now she gets a reward. The Indiana Blood Center gave her tickets to the Super Bowl in Indianapolis.