Mike Murphy worries that it might be, pointing to recent Democratic gains among Latinos and under-30 voters. Murphy's analysis jibes with the latest Pew study on political trends, which I recently wrote about here. Jay Cost takes issue with Murphy here. I think we can say three things: (1) Once a group chooses a party, it tends to stick with it for a long time, (2) "a long time" is not the same as "forever," and (3) rapid swings in party strength aren't unusual in American politics--as we saw in the period from 2005 to 2009 and, decades ago, from 1975 to 1981.