2008 was a long time ago, and it was notable at the time because it was already contrary to the overall trend of partisan polarization, which had been consistently escalating since the end of the long period of overlapping realignments that started in the 1930s and settled out in the 1990s. (Political polarization had been high in much of that realignment period, but because the major parties weren't coherently aligned around the high-salience issues that divided the public, that polarization was not strongly partisan.)