Speaking of chumming the waters, Charlie Cook notes a danger for Democrats:
Something that might be of concern to Democrats, however, is that in this year’s data, independents are tilting Republican by 18 points, 43 percent to 25 percent. This is even more than the 14-point edge that the GOP had in the 2010 polling (40 percent to 26 percent) and dramatically different from the 1-point Democratic edge in 2012 (35 percent to 34 percent). While independents tend to vote in smaller numbers than they do in presidential years, so do some of the strongest Democratic groups, namely minorities, youths, and, in particular, young women. These are the voters who made a huge difference for the Democrats in the 2008 and 2012 elections. This turnout disparity between midterm and presidential years spells trouble for Democrats. They overcame that obstacle in 2006 by running strongly among those independents who had turned on President Bush over the war in Iraq, among other things. The forces at work are considerably different this time around.
For Bush, it was his failure to deal with a bad situation in Iraq, or even to acknowledge the disaster we all watched unfolding. This time the disaster for the incumbent White House party can be summed up in one word: ObamaCare.