By contrast, in 2010, the senior vote dwarfed the youth vote in Ohio, Florida, Iowa, Pennsylvania and Colorado, among other states.
"The parties are paying more attention than ever to the senior vote.
"Florida is a symbol of the senior vote that's very critical in a lot of places," she said.
"If ever there was an issue that threatens the G.O.P.'s headlock on the senior vote, this is it," he said.
"The senior vote in Florida is a lot more complicated than it used to be," said Matthew T. Corrigan, a political scientist at the University of North Florida.
But there's little evidence Ryan's Medicare plan is a political winner and mounting evidence that it's currently a drag on the must-win senior vote.
But one senior Vote Leave source told the Guardian the intensity of the campaign had been such that "we think Cameron would be out by lunchtime".
A number of senior Vote Leave campaigners, including a cabinet minister, have told the Observer this need not and should not happen.
AARP's ambivalence will only embolden politicians who already have challenged the alleged unity of the "senior vote," realizing that it has long been fragmented by differences in income, ideology, education, race, religion, gender and marital status.
As the argument over Medicare intensifies, and the fight for the senior vote grows increasingly fierce, both campaigns are looking for ways to connect with a population that is not as digitally savvy.
