As Pete pointed out yesterday, the midterm elections did not turn merely on the enthusiasm gap. Independent voters — the Holy Grail of politics — turned decisively against the Democrats. Charlie Cook explains:

Beyond the symbolism and images, big mistakes were made and Democrats seem happy to blame President Obama and the economy and not accept responsibility for pursuing an agenda that turned independent voters, who had voted by an 18-point margin in 2006 for Democrats, to vote for Republicans by an 18-point margin in 2010, according to exit polls.

This huge shift from one midterm election to the next, by a group that constitutes 26 percent of the electorate, is seismic. It is not a matter of turnout or partisan intensity; it is a clear indication that Democrats alienated voters in the middle who saw an agenda in 2009 and 2010 that was quite different and much more ideological that the one described in 2006 and 2008.

But it would be a mistake for Republicans to assume, just as it was for Democrats following the 2008 election, that they now have this large and decisive group in their grasp. You want proof? Try Senate races in Nevada, Delaware, and Colorado. The danger for the GOP is that while independents have been dislodged from the Democratic coalition, they can easily be turned off by Republican candidates.

The challenge for the GOP, as it is in each presidential election, is to form a center-right coalition that can gin up enthusiasm among the base but also reach out to those not automatically within the fold. Part of the challenge is to define policy objectives, and part is persona. The GOP has made strides in formulating the former, but the latter — the search for the “hot but not too hot” salesperson — has yet to begin in earnest. The dramatic swing in the independent vote should remain a cautionary tale: it’s easier to lose the independents than to keep them moored to your party.