Dennis Kucinich's decision to ask his supporters to throw their support to Barack Obama in those caucuses (probably virtually all of them) where he cannot reach the 15% threshold is big news for the Obama campaign in a race that could be close, even though polls show Obama starting to pull away. Polls are especially unreliable here because of uncertainties about who will turn out.
Obama has directly started to ask voters for 2nd choice support, while quipping they "would be wiser" to vote for him as a first choice.
Hillary Clinton is in the same position that Howard Dean was four years ago, where early primary victories are thought to ensure the nomination. The strategic question for long-shot candidates is how do they best stop a front-runner from running away with the nomination.
My guess is that Kucinich's reasoning went something like this. An Iowa victory could make Clinton unstoppable for the Democratic nomination. A victory for John Edwards would not make Edwards unstoppable, but it might not derail the air of inevitability of the Clinton nomination; it might make Iowa irrelevant as it was when it went for Dick Gephardt in 1988 or favorite son Tom Harkin in 1992.
An Obama victory in Iowa, Kucinich likely reasoned, would be the biggest blow to Clinton's perceived inevitability. Because of Obama's much stronger base of national support than Edwards has, it would not make Iowa irrelevant. And, while an Obama victory in Iowa could create enough momentum to make Obama unstoppable, both the demographics of the country and strong base of the Clinton campaign, make an Obama victory less likely to lead to quick end of the primary battles than a Clinton victory would.
Whether or not Biden, Dodd, Richardson, Gravel, and company issue similar recommendations, or any recommendations at all, remain to be seen.
But I agree with what I perceive is Kucinich's view: a vote for Obama in Iowa is the vote most likely to keep the nomination from being wrapped up early. As both an Obama supporter and a frustrated Pennsylvanian (the Pennsylvania primary does not take place until April 22) I am glad that Kucinich made the choice he did.