The roughly one-eighth of voters who disapprove of Obama but nonetheless support Clinton for 2016 may be the most important group in the electorate. If Democratic candidates can collectively manage to corral Clinton’s share of the national electorate this fall, the party would likely keep control of the Senate and might take over the House of Representatives. The latter outcome is now seen (even by most Democrats) as a virtual impossibility. These Hillary Difference Voters, as we’ll call them, could find themselves the most courted contingent in this year’s contests.

Who are they? A comparison of those who back Clinton but disapprove of Obama with the group that is both pro-Clinton and pro-Obama suggests that the swing constituency is much more likely to be blue-collar and white — 71 percent of the mixed group are white, compared with only 57 percent of the pro-Obama, pro-Clinton group, and it is also somewhat more Latino. Whites without college degrees constitute 47 percent of the Hillary Difference Voters but only 30 percent of the pro-Clinton, pro-Obama group. In keeping with this, 62 percent of the Hillary Difference Voters have incomes of less than $50,000 annually.