Jason Reed / Reuters President Obama greets the audience after delivering remarks on education at the University of Colorado in Denver on Oct. 26, 2011

It’s well known that the U.S. is rife with political division: red vs. blue, the coasts vs. the interior, cities vs. rural areas, the 1% vs. the 99%. Less discussed is the yawning gap that has recently opened between young and old. America today is more politically divided by age than it has been in 40 years, according to a major new survey by the Pew Research Center.

TIME got an exclusive look at the poll, and in this week’s print issue, available online to subscribers, I have a story on its findings — specifically about the split that has developed between the so-called millennials, ages 30 and under, and the Silent Generation, ages 65 to 83. Testing a hypothetical matchup between Barack Obama and Mitt Romney, Pew found that millennials prefer the President by 26 points, while Silent Generation members tilt to Romney by 10 points. It might seem intuitive that younger voters are more liberal. But in the 2000 and ’02 elections, the two groups voted almost identically. It wasn’t until 2006 and ’08 that a broad gap opened up — one that narrowed slightly in 2010, as young voters tacked right, but is now wider than it was even in ’08.

What happened here? To a large degree, it seems, the split represents two very different reactions to change in American life. Pew found that seniors are unhappy about trends like immigration and diversity, and gay and interracial marriage. In one of the survey’s most striking facts, fewer than half of them say the Internet has been a positive development. And few things provoked livelier replies from the many seniors interviewed in Florida for this story than the impact of technology on American life. “Kids are running amok!” one told me. Millennials, by contrast, barely even register the idea that the Web might do more harm than good: only 11% call it a change for the worse.

More relevant for the 2012 election, 30-and-under Americans largely embrace the social changes that their elders reject. Millennials are twice as likely as Silent Generation members to call increased interracial marriage a change for the better (60% to 29%), and the divide is almost as great when it comes to gay marriage (59% to 33%). They’re more accepting of a growing Hispanic and immigrant population — in part because today’s young Americans themselves are a reflection of diversity. Forty percent of Americans 30 and under are nonwhite, more than double the proportion of Americans over 65.

Pew’s numbers show that millennials are less satisfied than Silent Generation members with their finances (perhaps because most seniors don’t have to worry about finding a job). That suggests social views are playing a major role in the political divide. It may be that Obama has become a focal point for the two generations, who see him as a representation of the diversity and change about which they disagree. Pew’s president, Andrew Kohut, thinks this might explain the rightward tilt of Silent Generation members. “There is this sense that comes out of the poll that Obama represents the changing face of America that some older people are uncomfortable with.”

Ultimately, however, this doesn’t mean that the cake is baked. Neither party can count on either of these generations. Pew’s numbers support the picture of a youth vote that is disillusioned with Obama and disengaged from the political process, meaning that overwhelming support for Obama among millennials might not yield a turnout that compares to the 2008 youth vote. (It’s probably not a coincidence that Obama has begun to zero in on the youth vote, including efforts like his new student-debt relief plan.)

Democrats can be cheered, meanwhile, that Silent Generation members have no abiding love for the GOP. They express roughly equal disdain for both major parties, while saying they trust the GOP more to handle most issues — with one exception: Social Security. (Pew did not ask specifically about Medicare, but I suspect the same might apply.) That gives Democrats an opening to pry seniors away in 2012 with a sharp message based on the threat of GOP entitlement cuts, much as they did en route to winning a House special election in New York earlier this year.

Such tactics and messaging will obviously be crucial in 2012. But the picture that emerges from Pew’s survey is that the 2012 election will be about something more basic: the changing nature of American society, and which generation’s view of that change will carry the day.

See the magazine story here, or check out the Pew Research Center’s survey here.