First daughter Jenna Bush isn't as committed to Republican candidate John McCain as her parents are, who are firmly behind the party's expected presidential nominee.

Jenna Bush told CNN's Larry King that she is open to learning about all the candidates -- including the Democrats.

King asked Jenna Bush and her mother, Laura Bush, who appeared with her, whether they had a favorite between Democratic candidates Barack Obama and Hillary Clinton.

"My favorite is the Republican," said Laura Bush.

Her daughter wasn't as sure.

"I don't know," Jenna Bush said. "I mean, who isn't open to learning about the candidates? But, I mean, and I'm sure everybody is like that. But I really -- I honestly have been too busy with books to really pay that much attention."

The Bushes appeared on King's talk show to promote their new book, "Read All About It."

Once bitter primary rivals themselves, President Bush supports McCain's bid to succeed him.

Separately, the first lady said she doesn't like the way the Democratic candidates talk about her husband.

"He takes a huge pounding from the other candidates, not all of them, not my candidate, John McCain, but I think that is -- that's demoralizing to me," Laura Bush said.