In the end, no single group will mean defeat for the Democrat and victory for the Republican in 2016. But President Obama's troubling legacy - a weakened coalition and growing ranks of alienated white voters - could mean a serious post-presidential hangover for Democrats.

Voters replaced Democratic senators with Republicans in Arkansas, Colorado, Iowa, North Carolina, Montana, South Dakota, West Virginia, and likely in Alaska, and appear on track to do so in a runoff next month in Louisiana. At the same time, voters kept Republicans in GOP seats in heavily contested races in Georgia, Kansas, and Kentucky. That is at least ten, and as many as a dozen, tough races, without a single Republican seat changing hands. Tuesday's voting was a wave alright - a very anti-Democratic wave.

Now that the 2014 elections are over and national politics is all about 2016, Democrats have good reason to worry that, for all his success at the polls, President Obama will leave his party with a toxic legacy.

A remarkably revealing portrait.

The Obama damage is two-fold. First, his success relied on a coalition that likely will not survive, or at least survive at full strength, without Obama himself on the ticket. Secondly, Obama drove a significant portion of white voters away from the Democratic Party.

In the end, no single group will mean defeat for the Democrat and victory for the Republican in 2016. But President Obama's troubling legacy - a weakened coalition and growing ranks of alienated white voters - could mean a serious post-presidential hangover for Democrats.

Some Democrats and their advocates in the press believe Obamacare, a year into implementation, is no longer much of a factor in the midterm elections. But no one has told Republican candidates, who are still pounding away at the Affordable Care Act on the stump. And no one has told voters, especially those in states with closely contested Senate races, who regularly place it among the top issues of the campaign.