To put it into terms Liberals can understand: Dion is the one who stands the best chance of delivering victory to the Liberal Party, not an election or two from now, not after another five or nine years of Tory rule, but in the one that's going to happen next year.
Look at the other options:
First there's Ignatieff. A good candidate, a man who could certainly lead a country. But his electoral weaknesses are obvious, and easily exploited. He supported the war in Iraq. Granted, so did I, and for the exact same reason as Ignatieff no less. But pragmatically, this is a problem. There are a sizable contingent of Liberal/NDP swing voters, and as we all know, that particular issue is a volatile one for the left. The left-leaning among us generally hate the war, and anything associated with it. Associating the Liberal Party with it is a recipe for electoral disaster. Then there's the secondary issue, that he's been out of Canada for the past twenty-five years. Don't think voters won't take notice of something like that. The fact is, we cede some of our strongest strengths if Ignatieff becomes the leader. It wouldn't guarantee an election loss, but it would make a win harder.
Then there's Rae. What else needs to be said? Rae is a huge risk in Ontario, a place where the Liberals have already lost far too much ground. If the Liberals lose the 905 belt - which could very well happen if Rae leads the party - they will lose the election. Period. Like Ignatieff, Rae's political weaknesses are obvious and easily exploited.
Kennedy's problem is less open to exploitation, but still a problem nonetheless. With 1% of the delegates in Quebec, it should be pretty clear that Kennedy is not a favourite there. And why should he be? Of the four major contenders, his French is by far the weakest. In the election, he would be going up against a very popular favourite son (Gilles Duceppe) and a fluently bilingual sitting prime minister whose party is determined not to lose the ground they've gained in Quebec. Will Kennedy lose seats for the Liberals in Quebec? Maybe. Can he pick up any more seats there? I highly doubt it.
Which brings us back to Dion. Polls have consistently shown that the only candidate who stands a realistic chance of defeating the Bloc in Quebec is Stephane Dion. The Liberal party cannot gain any more ground than they already have this time around in Atlantic Canada or the West. It's about Ontario and Quebec. Ontario would vote for Kennedy, but Quebec wouldn't. Conversely, Quebec could and likely would vote for Dion, and Ontario would not be a problem. Dion may be less well known there, but that doesn't mean he will be less successful. Complaints about his weak English (which is actually judged by professional linguists as fluent) making him vulnerable in Ontario can be directed to a Mr. Jean Chretien.
Moreover, Dion's weaknesses, while existant, are not as immediate or easily exploitable. Granted, he wasn't entirely successful with the environment portfolio. But that is hardly an election-losing weakness. Any talk of perceived anger over the sponsorship scandal being directed at Dion is a myth, supported by no factual data. In fact, polls have shown that Dion is not associated in the Quebec public's mind with that particular scandal.
It seems to me quite obvious who the next leader ought to be. The one who stands the best chance of winning.