He did not immediately reply to Palin's mention of his son, Beau, the Delaware attorney general, who is scheduled to fly to Iraq with his National Guard unit on Friday.

For much of the evening, the debate unfolded in traditional vice presidential fashion-- the running mates praising their own presidential candidate and denigrating the other.

Palin, who has been governor of her state less than two years, was under intense pressure to demonstrate a strong grasp of the issues as she stepped onto the stage.

Pre-debate polls show the public has become increasingly skeptical of her readiness for high public office.

It is still too early to tell if her performance in the debate improved her image.

Democratic vice presidential nominee Senator Joe Biden (D-DE) (L) and Republican vice presidential nominee Alaska Governor Sarah Palin (R) smile as they chat onstage at the end of their vice presidential debate at Washington University in St. Louis, Missouri, Oct. 2, 2008. [Xinhua/Reuters]

(Xinhua News Agency October 3, 2008)