For the actual sports analysis, I'm going to point you to people who might know about sports, or at least Matt Yglesias' statistically driven musings on the NBA. But I know you're really wondering how James' decision will affect the midterm elections. Can Lebron provide a sweet assist to House Speaker Nancy Pelosi? Or at least pull down a board for the height-challenged Harry Reid?
Maybe! We have some research that suggests voter happiness contributes to support for the incumbent party, which is what the Democrats want -- for instance, several researchers found during the 2009 NCAA Men’s College Basketball Tournament that "sports-induced emotional change affects approval of President Obama and assessments of the health of the country." Others have discovered that "if a local college football team wins a match in the ten days before a Senate, gubernatiorial or even presidential election, the incumbent candidate tends to get a slightly higher proportion of the vote."
James' impact, presumably, would increase because of his relative importance and the absurd media hype around his choice -- he's going to make some basketball fans pretty happy. He could end up in a number of places: Staying in Cleveland, Ohio, or going to Miami, New York, Chicago, or New Jersey, although both New Jersey and New York seem like longer shots at this point.
His decision will have two impacts: Disappointment and enthusiasm. If he leaves Ohio, disappointment there could be a killer for the Democrats, where they have close Senate and gubernatorial races and a number of House races that will be tight -- but heading for Miami, New Jersey, or even Chicago could help boost threatened incumbent Democrats in those states and perhaps provide a boost for similarly tight Senate races in Florida and Illionois. A Chicago arrival could even be taken as a tacit endorsement of President Barack Obama's health-care plan!
Ultimately, the best outcome for the Democrats would be for James to stay in Cleveland, rewarding his constituents institutional loyalty and inclining them to vote for the incumbents while minimizing disappointment. The worst outcome would be for James to go to New York, which would maximize Cleveland's disappointment and provide little boost, since there are so few competitive races in New York this year.
Either way, there will be dunking.
-- Tim Fernholz