Concerned by changes to Medicare and compelled by a Republican Party that promised a return to America’s glory days, seniors played a crucial — and often understated — role in races across the country. They were unswayed by ubiquitous Democratic warnings about Republican changes to Social Security. And they put a series of campaigns out of reach for Democrats…

The shift in older voters was the most dramatic swing of any age group, George Mason political scientist Michael McDonald said, and it gave the GOP the “magnitude” of its victory.

In the 2006 midterm campaign (regarded as a more useful basis of comparison than high-turnout presidential elections), voters 65 and older essentially split their vote evenly between Republicans and Democrats — a stark comparison with 2010. But that’s not the only noticeable change in voting patterns: In this cycle, in addition to losing the senior vote by more than 20 points, older voters also grew as a share of the overall electorate. In 2006, seniors made up 19 percent of the voting public; this year, they represented 23 percent.