A diary at Pols notes John Hickenlooper's dance as he tries to differentiate himself from Bill Ritter and Bill Ritter's record. It struck me as interesting that Ritter came out last and flatly stated that he would be endorsing Hickenlooper. In early 2006 Bill Ritter had been a candidate for many, many months while Andrew Romanoff and John Hickenlooper dithered about throwing their hats in the ring. Finally the Democratic Party coalesced around Ritter in the spring of 2006, culminating in a unity rally on the west steps of the Capitol with Romanoff, then Senate President Joan Fitz-Gerald and other Democratic leaders. Hickenlooper was noticeable absent.
The Mayor didn't endorse Ritter until the last week or so of the campaign in 2006. The Mayor's refusal to endorse was viewed as an arrogant snub by Ritter and his advisers and has been a sore spot ever since. The Mayor and the Governor have not only never been close, there's been an obvious disdain for each other for many years.
I don't imagine that Hickenlooper will be shy about distancing himself from Bill Ritter as the campaign goes on.