NEW DELHI (AFP) - Rahul Gandhi, tipped to be India's next prime minister, was regarded as an "an empty suit" when he was given his first major political post four years ago, according to a leaked US diplomatic cable. Sonia Gandhi, Rahul's mother and the president of the ruling Congress Party, appointed her son to the post of party general secretary for youth affairs in 2007, a move seen as cementing his position as heir apparent. A confidential cable from the US embassy, which carried the signature of the then-US ambassador David Mulford, said little was known at the time of the media-shy Rahul's personal politics.