Shifting tides for Obama in 2012

The personalities and characters of candidates, the cut and thrust of campaign tactics and the interplay of issues all help decide elections. But the daily battles of a campaign play out on ground shaped by long-term population change.

The growing Latino population, for example, has buoyed Democratic fortunes and gives Obama hopes of holding on to Nevada, despite that state's punishing economy. Increasing numbers of highly educated professionals keep his chances alive in Virginia, which he was the first Democrat to carry since 1964. Colorado, a state that ranks high on both counts, is a major prize Democrats hope to keep.

By contrast, many strategists believe that states like Ohio, where both college graduates and minority voters are scarcer, could prove far more difficult for the president unless he catches a significant break on economic conditions in the next year.

More is at stake than just Obama's future. After their victories in 2006 and 2008, Democrats hoped that changes in the U.S. population had delivered them a stable, lasting majority. Now, as the rising demographic tides crash against the rocks of an economic collapse, they see that advantage slipping away.

No matter the demographics, a party in power "still has to deliver" for the voters who supported it, said political analyst Ruy Teixeira, who, shortly after President George W. Bush took office, co-wrote a book correctly predicting the Democratic resurgence.

"Voters have to feel they're getting what they need, and at this point that's very much in question," he said.

To win, Obama needs big margins among his two core groups, minorities and college-educated white professionals, plus a reasonable share of whites without college degrees -- the working-class voters who formed the bedrock of the Democratic majority in the 20th century, but who now tend to vote Republican.

Right now, he's in danger on both sides of that equation.

Democrats have won large majorities among nonwhite voters for years, but only in the last decade has that vote become large enough to swing national elections. When Richard M. Nixon profited from white backlash against the civil rights movement and captured the formerly Democratic South, nonwhites made up only about 1 in 10 voters, Teixeira noted. By 2000, nonwhites were almost 20% of the vote.

By 2008, they made up a quarter of the electorate. Obama won the lion's share of their votes -- 95% of blacks and two-thirds of Latinos. In 2012, their numbers will tick up yet again.

To win in places like Colorado, Nevada and New Mexico -- all key targets -- Obama needs the Latino vote to keep expanding and to go heavily to him. In North Carolina, another closely fought state the last time around, his chances depend in part on a very large and loyal black turnout.

Yet minorities have been hit disproportionately hard by the recession -- unemployment rates are higher among blacks and Latinos than among whites, and poverty is deeper.

The grim economic numbers almost certainly will discourage some from voting. The economy could even encourage some Latinos to consider the Republicans -- although the hard line the GOP candidates are taking against illegal immigrants may lessen that prospect.

The other key for Obama is the strong support that Democrats have developed among professionals -- lawyers, college professors, nurses, social workers, teachers. That group makes up almost a fifth of the electorate, and its members tend to share the Democratic belief in government as a force for public good.

Republicans still triumph among a different group of college graduates -- business owners and managers. But Obama beat John McCain by 19 points among voters who have education beyond a college degree -- an indicator of his strength among professionals.

In 11 states plus the District of Columbia, more than one-third of the white residents have college degrees, according to the latest government statistics. Obama carried all 12 in 2008. By contrast, of the 10 states with the lowest percentage of college-educated whites, Obama carried only one -- Indiana, and strategists in both parties assume he will lose it this time around.

Going into 2012, Obama's standing with college graduates has fallen, as it has across the board. Nonetheless, the states with the largest percentage of college-educated whites, including California, Massachusetts, Maryland, Connecticut, New Jersey and New York, remain the most solid parts of Obama's electoral base.

But in states where the college-graduate percentage is lower, his prospects seem increasingly glum.