decision not to run has altered the landscape of the race in a significant way. Each time this happens, Elephant Watcher will recalculate the odds and issue an explanation for the changes. Each candidate's chances of winning the nomination are determined based on whether his unique "winning scenario" is likely to occur. An explanation of these scenarios and a graph of the race's changes over time may be found on the Rankings page.
The short version: Pawlenty benefits the most, as he and Daniels were somewhat interchangeable. Another of Pawlenty's main competitors in Iowa is gone; even better, Daniels will no longer split their vote.
Christie +2% -- The loss of another decent candidate from the field creates a bigger vacuum--and a greater desire for someone new to fill it. Anyone looking for an electable candidate who doesn't like either Pawlenty or Romney will now be even more dissatisfied with the field.
Pawlenty +8% -- Daniels and Pawlenty were similar in that they each have high perceived electability and conservatism, but are not Tea Party favorites. They also lack charisma. With Daniels gone, Pawlenty may claim the mantle of "electability" in Iowa. Aside from Christie, Pawlenty now has the best chance of winning the Iowa Caucus. He is the chief anti-Romney.
Romney -2% -- When a candidate leaves the race, it normally benefits every other candidate. However, Daniels' departure increases the odds of Pawlenty winning Iowa, and this hurts Romney. Romney's best-case scenario--other than winning Iowa himself--is for an unelectable Tea Party candidate to win there, forcing the Republican establishment (and any other strategic voter) to support the winner of New Hampshire (likely Romney). If Pawlenty wins Iowa, there's no great urgency for these voters to support Romney.
Cain -- There's a net-zero for Cain. On one hand, Cain's competitor in Iowa is assisted, which is bad. On the other hand, Cain will move up in the polls and increase his chances of being included in the major primary debates. He needs this to gain an aura of legitimacy as a candidate--despite having never held elective office.
Gingrich -- Gingrich is largely unaffected, fighting battles of his own.
Palin -1% -- Palin's only hope of winning Iowa is if the "establishment approved" candidates have their votes split. With Daniels gone, this is less likely to occur.
Santorum -- Some of Daniels' supporters might go to Santorum, but not enough. He needs a split vote more than anyone, and it is less likely to occur. He is unaffected, since his chance of winning the nomination is already 0%.
Paul -- As with Santorum, he needs his competitors to be split. His chances of winning are also at 0%, so things can't get worse.