Nationally, the decline of the white share of the electorate continued, dropping to 72 percent, down from 74 percent in 2008 and 77 percent in 2004.
Meanwhile, the Hispanic share grew again, reaching one in 10 voters nationally for the first time ever, and as high as 37 percent of the electorate in New Mexico.
"The country is changing, and the people our party appeals to is a static group," Republican strategist Mike Murphy said.
Obama was able to hold much of his 2008 electoral map in large part because Republicans performed so poorly among Hispanics, the nation's fastest-growing ethnic group and one that is transforming politics in states once reliably conservative, such as Virginia, Florida, Nevada, and Colorado.
Obama won 71 percent of the Hispanic vote, exit polls found, and Romney garnered just 27 percent, below what John McCain got in 2008 (31 percent) and what former President George W. Bush received in 2004 (from 33 percent to 44 percent, depending on the poll).
Many Hispanics have bristled at increasing Republican attacks on illegal immigration, tough talk that many consider insulting or insensitive. Yet the GOP, six years after Bush's proposed immigration overhaul went nowhere, is dominated by conservatives who oppose "amnesty" for those who entered the country illegally.
Although he softened his tone in the fall campaign. Romney enthusiastically took a hard line in the primaries, including the concept that illegal immigrants should "self-deport," or leave the country immediately.
"Mitt Romney self-deported himself" with Latinos, said Florida-based Republican strategist Ana Navarro. As a party, she said, "if we don't do better, we're going to be shut out of the White House forever."
Party pros say the GOP needs to embrace more balanced immigration policies that would provide an avenue toward citizenship, or legal residency, for undocumented immigrants who have obeyed the law.
"Ten years from now, you want to be splitting the Hispanic vote by something close to 50-50," said antitax activist Grover Norquist, a leader of the conservative movement. "That's completely doable if the threat of deportation was removed. But it's not doable as long as that's hanging over, and some Republicans talk as if they're for the deportation of your mother or your aunt."
Exit polls also showed Obama winning the overwhelming support of young voters and African Americans, and their share of the electorate did not shrink compared with 2008, as preelection polling had suggested might be the case.
Blacks made up 13 percent of the national electorate in the historic 2008 election, when Obama became the first African American president. Despite four years of economic troubles and some disappointments, blacks constituted 13 percent of the electorate Tuesday as well. African American neighborhoods in Philadelphia reported turnouts rivaling those of 2008.
Nationwide, Obama won the votes of 93 percent of African Americans.
Nonwhite voters made up 28 percent of the electorate this year, up from 26 percent in 2008. Obama won 80 percent of these voters, the same as four years ago.
Voters aged 18 to 29 made up 19 percent of the electorate, up a percentage point from four years ago. Obama carried the group 60 percent to 37 percent this time.
Peter Levine, a Tufts University researcher on youth participation in politics, argued Wednesday that young people were critical to Obama's having carried Pennsylvania, Ohio, Virginia - and likely Florida, where the outcome was still undecided but the latest unofficial numbers gave the president a narrow lead.
"If you wipe out the youth vote or allocate it 50-50 . . . those states switch from blue to red and Mitt Romney is the president of the United States," Levine, director of the Center for Information and Research on Civic Learning and Engagement at Tufts, said in a conference call with reporters.
If some Republicans are beginning the period of soul-searching that often accompanies back-to-back losses for political parties, others say the problem was in nominating Romney, who had a centrist profile he had to live down to win the nomination. The GOP should stay true to its conservative orientation, they say.
"Mitt Romney's loss was the death rattle of the establishment G.O.P.," said Richard A. Viguerie, chairman of Conservative HQ.com and a pioneer in political direct-mail advertising. "Far from signalling a rejection of the Tea Party or grass-roots conservatives, the disaster of 2012 signals the beginning of the battle to take over the Republican Party and the opportunity to establish the G.O.P. as the party of small-government constitutional conservatism."
Ralph Reed, a leader of a conservative evangelical Christian organization, said purity vs. pragmatism was a false choice.
"If the Republican Party wants to be competitive in national elections, it will have to nominate candidates who can appeal to young voters, women, Hispanics and other minorities," Reed said in a statement. "The good news is, many of those voters are conservative and are people of faith."
Contact Thomas Fitzgerald
at 215-854-2718 or firstname.lastname@example.org, or follow on Twitter @tomfitzgerald. Read his blog, "The Big Tent,"
at www.philly.com/BigTent. Inquirer wire services contributed to this article.