Despite attempts by Democratic Senate strategists to make “the map is the map” the new “it is what it is,” the Senate map was not the biggest problem facing Democrats this year. A bad Senate map does not account for Republican governors in the Democratic strongholds of Illinois Maryland and Massachusetts or a seven point win for Republicans in the National House Vote.

In reality (and to their credit, some Democrats HAVE been willing to admit this), the biggest problem for Democrats this year was President Obama and his lackluster approval rating, which currently sits at 42{09f965da52dc6ab4c1643a77bd40d1f729d807040cd8db540234bb981a782222} in the Real Clear Politics average.

The frightening thing for presumptive Democratic nominee Hillary Clinton and other Democrats on the ballot in 2016, is that, if history is any guide, President Obama’s approval rating will be even worse in two years. As the table below shows, the past five Presidents have seen their approval rating drop in the two years between the midterm election and the year they were either defeated or term limited.

Due to the resiliency of President Obama’s base, it is doubtful that his approval rating will dip into the low to mid 30s, but he will have to buck historical trends if he hopes to even move his approval rating back up to the mid 40s.

As a result, it is likely that eight years after he defeated her in the Democratic primary, Barack Obama will again be the biggest obstacle between Hillary Clinton and the White House.