He's just seat warming for Shorten in case they fall over the line at the election. Razaar has it right, read the book and find out what a miserable piece of work KR is.
This Rudd/Gillard/Rudd situation reminds me of Proverbs 26:11, "As a dog returns to its vomit, so fools [in this case, the ALP] repeat their folly." Or PJ Keating's quote regarding Andrew Peacock, "Can a souffle rise twice?"