There's already been some good examination of how much the age gap between John McCain and Barack Obama will matter in November. ThingsYoungerThanMcCain.com, for example, is doing the yeoman's work of listing the many, many items—like lubricated condoms and the LP record—that are younger than McCain.
And the folks at the Pew Research Center conducted a poll in February that found 26 percent of registered voters think John McCain is too old to be president (the number jumps to 32 percent when voters are told that McCain is 71).
We know that Barack Obama will be 47 on election day and McCain will be 72, meaning that 2008 will see a larger age gap between the top two presidential candidates than any of the previous 55 presidential elections. So here's my question: how has age played in presidential elections in the past? Let's look at a chart (takeaways at the bottom):