For most of the past two decades the Grand Old Party didn’t actually get its support from older voters. Not very long ago the Democratic party had an advantage with senior citizens but that has disappeared since President Obama took office. From Gallup:

Democratic Advantage in Party Affiliation, by Age, 1992-2013

The demographic reversal is huge and one of the most significant things that has happened in American politics. It is especially important because age groups don’t turnout in similar rates in every election. Older voters are more likely than young voters to turnout in midterm elections. When combined with the Republicans built in advantage from the design of the Senate and the last House redistricting this creates a perfect storm.

There are likely many causes for this change. Racism directed at the first black president and the fact that Democrats are now openly helping to win the “culture wars” probably both play some role, but I suspect it is Obama’s endless push to cut entitlements that is the single biggest cause.

Republican really began getting traction among seniors during the health care fight when they attacked Democrats for cutting $700 billion from Medicare. It was one of the most repeated attacks in 2010. While it was unfair to attack Democrats for reforming the broken Medicare Advantage system, Obama made it impossible for Democrats to counter this narrative by also pushing for a “grand bargain.”

Even if Democrats didn’t really cut Medicare benefits with the Affordable Care Act, at the same time they were still pushing to actually cut Medicare and Social Security benefits with different legislation. The “we didn’t cut it yet but we want to” is a terrible response to these GOP attacks.

The Democratic party’s biggest appeal to white seniors was defending entitlements. That was their brand. You can’t be the defenders of entitlements when you are the party pushing for benefits cuts and the only party actually putting the cuts in your budget.

Once Obama took this main economic selling point from Democrats there was not much appeal left for older voters. On social issues seniors tend to be more aligned with Republicans, so Democrats can’t afford to be merely as bad as Republican on entitlements — but that is exactly what a push for a grand bargain did. By its very nature it was trying to make the parties equally bad on entitlement cuts.

This loss of older voters might be one of the most significant political responses to Obama’s presidency. It certainly played a role in costing Democrats the House and could potentially help cost them the Senate.