"They have put together a coalition of populations that will eventually become the majority or are marching toward majority status in the population, and populations without whom it will be very difficult to win national elections and some statewide elections, particularly in states with large black and Hispanic populations," Harrison said.
One way to see the trend is to look at the diversity of young voters. Among voters under 30 years old this year, only 58 percent are white. Among senior voters, 87 percent are white.
Brookings Institution demographer William H. Frey says policymakers and politicians need to prepare for a growing "cultural generation gap."
"Both parties are getting the message that this is a new age and a new America," says Frey. "Finally, the politics is catching up with the demography."
Just as Republicans need to do a better job of attracting Hispanics, says Frey, Democrats need to do more to reach out to whites.
The face of Congress is changing more slowly than the electorate or the population, but changing it is.
House Democratic leader Nancy Pelosi of California was happy to highlight the news that for the first time in history, more than half the members of her caucus next year will be women, black, Hispanic or Asian. She said it "reflects the great diversity and strength of our nation."
House Speaker John Boehner of Ohio, whose caucus is far more white and male, said Republicans need to learn to "speak to all Americans — you know, not just to people who look like us and act like us."
Former Secretary of State Condoleezza Rice, one of the GOP's most prominent black women, said the party needs to understand that "the changing demographics in the country really necessitate an even bigger tent for the Republican Party."
"Clearly we are losing important segments of that electorate and what we have to do is to appeal to those people not as identity groups but understanding that if you can get the identity issue out of the way, then you can appeal on the broader issues that all Americans share a concern for," she said.
All sides know the demographic trends are sure to become more pronounced in the future.
In the past year, minority babies outnumbered white newborns for the first time in U.S. history. By midcentury, Hispanics, blacks, Asians and multiracial people combined will become the majority of the U.S.
Since 2000, the Hispanic and Asian populations have grown by more than 40 percent, fueled by increased immigration of younger people as well as more births.
Currently, Hispanics are the largest minority group and make up 17 percent of the U.S. population, compared with 12 percent for blacks and 5 percent for Asians. Together minorities now make up more than 36 percent of the population.
Hispanics will make up roughly 30 percent of the U.S. by midcentury, while the African-American share is expected to remain unchanged at 12 percent. Asian-Americans will grow to roughly 8 percent of the U.S.
"The minorities will vote," said demographer Frey. "The question is will their vote be split more across the two parties than it was this time?"
For both Republicans and Democrats, he said, the 2012 election is a wake-up call that will echo through the decades.
AP Director of Polling Jennifer Agiesta, Associated Press News Survey Specialist Dennis Junius and writer Hope Yen contributed to this report.
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