Obama's Victory & 2004 Bush Voters

In a forthcoming article in PS, Arthur Lupia suggests that the behavior of 2004 Bush voters was key to President Obama's victory in 2008:

Barack Obama’s success in bringing millions of new voters to the polls was an impressive achievement. But these new voters were not a necessary condition for his victory. When considering whether or not to support John McCain in 2008, a number of Bush voters decided, “No We Can’t.” The number of 2004 Bush voters who decided to stay at home, or to support a Democrat, in 2008 did not grab the same kinds of headlines as new voter stories, but they were a sufficient condition for Obama’s Electoral College victory. Hence, future presidential hopefuls’ attempts to draw lessons from the 2008 campaign should focus not only on how the Obama campaign got so many new people to the polls, but also on why so many people who voted for a Republican presidential candidate in 2004 chose to do something different in 2008. If 2008’s new voters are less energized in 2012, the story of that election may turn on whether voters who once supported a Republican can be convinced to do so again.