From McClatchy:

When Missouri Sen. Claire McCaskill endorsed Illinois Sen. Barack Obama, she said she’d found a candidate who “gives us a reason to believe again.”

Obama believed in her, too, donating $10,000 from his political action committee to McCaskill’s 2006 campaign. She received nothing from the PAC of New York Sen. Hillary Clinton.

And when California Rep. Doris Matsui endorsed Clinton, she said the former first lady had been “a consistent champion and friend” of Asian Americans. Clinton’s PAC had also befriended Matsui, giving $5,000 to her campaign. Matsui received nothing from Obama’s PAC.

Both McCaskill and Matsui are among the nearly 800 superdelegates who’ll have a big say in who heads the Democratic ticket this fall. While both women say the PAC contributions didn’t influence their choice for president, a study by the Center for Responsive Politics concludes that campaign contributions have become a fairly reliable predictor of whose side a superdelegate will take.

And if that’s the case, it’s good news for Obama. Since 2005, his PAC has donated $710,900 to superdelegates, more than three times as much as Clinton’s PAC has. Her PAC distributed $236,100 to superdelegates during the three-year period.