Federal appeals court judge Diane Wood and Solicitor General Elena Kagan, two candidates for the impending vacancy on the Supreme Court, took part in a conference Wednesday on the importance of judicial independence.

Kagan gave the keynote address at the daylong event that also included a lunchtime speech by retiring Justice David Souter.

Wood, who serves on the U.S. Court of Appeals for the 7th Circuit in Chicago said she had long planned to attend the conference, but she would not answer any questions about the court.

She declined to say whether she was visiting the White House during her stay in Washington.

Wood and Kagan are among the candidates the president is considering to replace Souter, according to officials familiar with President Barack Obama's thinking.

Also attending the day's panel discussions at Georgetown University Law Center were Justice Stephen Breyer and retired Justice Sandra Day O'Connor, who has led the annual event since her retirement from the court in 2006.

She noted that Souter is "going to join me in that now very exclusive group of retired Supreme Court justices. His presence will double the membership."