Cass Sunstein, who is married to Irish genocide expert Samantha Power, has been tipped as a possible successor to US Supreme Court Judge David Souter who is retiring in June.

Sunstein, who directs government policy on issues such as technology and privacy, has long been considered one of the foremost legal scholars in the nation and had been widely rumored to be President Barack Obama’s first Supreme Court choice.

Power sparked off a furious row during the 2008 presidential election campaign when she described Hillary Clinton as a “monster” during an interview with a Scottish journalist. She resigned, but later won a plum post at the National Security Agency.

She often works with Clinton on foreign policy issues such as genocide and Darfur and the two are said be cordial.

Both Power and Sunstein are very close to the president, and he mentions them both in his second book “The Audacity of Hope.”

The couple, who were married in Ireland last year, recently had their first child Declan.