In a race destined for multiple ballots, the Liberal leadership comes down to a question of growth. Which candidate can build support past the first ballot and ride that momentum to victory. I think it important to acknowledge the power of psychology as the primary determining factor.
Most of Ignatieff's detractors argue that while he may well lead on the first ballot, he will stall, allowing another candidate to snatch the prize. I think this assumption falls apart if Ignatieff has a strong showing on the first ballot- a third or more. It becomes especially risky for other candidates to move to someone else, if Ignatieff looks the likely winner. The political future of a candidate may rest with who they ultimately support, a strong showing by Ignatieff may provide a powerful motivation to get on the bandwagon. Unless candidates are sure others will move to someone other than Ignatieff, their support may cancel out and give Ignatieff all he needs to get over the top. Important to remember, if Ignatieff has say 35%, he only needs to pick up less than a quarter of the remaining delegates, which isn't a stretch. Stop Iggy may be unrealistic, because it will require a herd mentality amongst delegates.
Despite all the talk about who is everyone's "second choice", the only person who will have any chance will be the second place person on the first ballot. If someone like Dion finishes third or fourth, it's unlikely that sympathetic delegates will move on masse to a risky perch. The battle to be the anti-Ignatieff will be won on the first ballot, unless of course the numbers are so close as to be meaningless. Anything around 20% would be a strong showing, and provide a reasonable alternative to Ignatieff, especially if he comes in at 30% or slightly higher. Delegates won't see any hint of "inevitability", but will be tempted to move to the second place candidate. It is for this reason that I disagree with people who argue that Kennedy has less potential than Dion. If Kennedy finishes second, I think Dion is essentially dead. Afterall, despite the spin, it's not as if people hate Kennedy. The momentum of a strong first ballot percentage will be the determining factor for Kennedy's growth.
Third place only matters if the numbers are essentially the same as second place. Any gap of say 3% should be enough to get the momentum required. A small percentage, but in a crowded field where people are shopping, a powerful indicator. I don't see how anything less than second is possible for Rae, who must show his baggage isn't an albatross. If Rae were to finish second, I think people would be surprised at his ability to grow. Likely to have an impressive speech, the moment and charm may override the concerns.
It's all speculation of course, but I see where Ignatieff sits and who finishes second as the only factors that matter when we speak of growth.