The strengths of the rival Democratic contenders among specific groups of voters in Tuesday's elections offer a guide to the contests in the weeks ahead.
Sen. Barack Obama built his big victory in South Carolina last week on a coalition of highly educated, affluent professionals, young voters and African-Americans. He also showed great strength among highly educated, affluent white voters in New Hampshire, a state with a minuscule black population.
Obama's performance nationwide on Tuesday indicated that he can rely on this coalition to deliver victory in some states — but not all.
Across the nation in Tuesday's contests, Sen. Hillary Clinton often beat Obama among older, less wealthy and less educated voters, suggesting both the limits of his appeal and where she can concentrate her efforts for votes in the next primaries.
Here’s how Clinton and Obama performed among crucial parts of the electorate.
San Bernardino and Riverside Counties in the "Inland Empire" of southern California are home to hard-working, hard-pressed people who endure long commutes because they couldn't afford to buy home in the Los Angeles housing market.
The two counties also rank among the top counties in the nation for real estate foreclosures.
Clinton appealed to voters in these two counties far more than Obama did: she won three-fifths of the vote in each county.
Clinton also beat Obama by a huge margin in Fall River, Mass., a city of traditional Catholic, socially conservative, working-class voters. Clinton won 77 percent of the Fall River vote, to Obama’s 19 percent. Clinton also trounced Obama in the white working-class town of Haverhill, Mass.
This suggests Obama has a problem — similar to one seen in the New Hampshire results — with less affluent, non-Ivy League, white Democrats.
But conflicting evidence comes from Waterbury, Conn., an old industrial city that Sen. Joe Lieberman carried by a landslide over anti-war challenger Ned Lamont in the 2006 Democratic Senate primary.
Clinton needed a similar margin in Waterbury in order to win statewide, but Obama won the city with 51 percent of the vote.
In the far suburbs of New York City, Suffolk County is a good specimen of a once-Republican county turning more Democratic.
Many working-class white voters here cast ballots for George Bush in 2004 — he got 48 percent in this county — but they may be open to a Democratic presidential candidate this year.
Obama got 35 percent of the vote in Suffolk. Clinton had an advantage here since New York is her home state.
A California splitIf you think of wineries, redwood trees, and coastal vistas when you think of California, then you have a picture mostly of Obama's California.
Obama's highest percentages were in northern California. He carried San Francisco and Alameda County, which includes Berkeley and Oakland.
Drive north across the Golden Gate Bridge and head to Marin, Sonoma, Mendocino, and Humboldt counties and you are in Obama Country.
But if you drive south or head inland away from San Francisco, you would generally be in Clinton Country: she won such inland counties as Sacramento, Fresno, Imperial, Kern and Riverside.
And most importantly she easily beat Obama in the three counties that cast the highest number of Democratic votes in California: Los Angeles, San Diego, and Orange counties.
Despite losing Massachusetts statewide, Obama won nearly 60 percent of the vote in Northampton, home of Smith College. He also won 53 percent of the vote in Wellesley, Mass., home of Clinton’s alma mater, Wellesley College.
Middletown, Conn., and New Haven, Conn., are the homes to Wesleyan University and Yale University. Obama won Middletown with 54 percent of the vote, about the percentage Lamont won in 2006. Obama won New Haven with two-thirds of the vote, far out-performing Lamont’s 51 percent in the 2006 primary. New Haven has a significant black population.
Obama also carried Tompkins County, N.Y., home of Cornell University.
Affluent left-of center voters
Obama performed well in such wealthy, liberal places in the New York City suburbs as Westport, Wilton and Greenwich, Conn. and California left-of-center places such as Marin County and Santa Cruz County.
The Connecticut exit poll interviews indicated that, as he had in New Hampshire, Obama performed extremely well among voters earning more than $200,000 a year.
He also got three-fifths of the Connecticut vote among those who had done post-graduate study. In California, he got 53 percent of the vote among voters who had done post-graduate study.
Exit poll interviews with Democrats in California, Connecticut and New Jersey revealed that Clinton was far more popular with Catholic voters than Obama, beating him by anywhere from 20 to 40 percentage points.
Obama won caucus states that put a premium on grass-roots organizing among party activists, scoring victories in Idaho, Kansas, Minnesota and North Dakota — states that include plenty of rural places.
But in central Tennessee, in the counties represented by one of the most conservative Democratic House members, Rep. Lincoln Davis, Democrats much preferred Clinton to Obama, giving her 70 percent of their votes.
The pattern held true in rural Missouri counties represented by centrist-conservative Rep. Ike Skelton. Clinton garnered two-thirds or more of the vote in such counties.
Clinton carried the five counties in Arizona with the highest percentage of Latino residents; likewise in California, she won the top five Latino counties.
Exit poll interviews with California Democrats indicated that Clinton beat Obama among Latino voters by two-to-one. He fared better among Latino voters in Arizona, getting 43 percent to Clinton’s 53 percent.
As he did in South Carolina, Obama scored big margins of victory in places with big black populations.
Obama won Tennessee's Shelby County, which includes majority-black Memphis, with 70 percent.
The Illinois Democrat won the city of St. Louis with better than seven out of 10 votes. He won three-quarters of the vote in Fulton County (Atlanta), Georgia.
Over age 65 New Deal/ Truman Democrats
East Haven, Conn., is the home of the older New Deal Democrats who supported Lieberman in his 2006 primary battle against Lamont. Clinton outdid Lieberman here on Tuesday, getting 70 percent of the votes in this town, 5 points better than Lieberman got in 2006.
Nassau County, N.Y., has one of the highest populations of people over age 65 of any county in the nation, with 15 percent over age 65. This is Clinton home turf so it’s hardly surprising that Obama did not win this county. He got 35 percent.
Obama apparently had trouble appealing to older voters in New York, getting only one-third of them; he performed only slightly better among over age 65 voters in New Jersey, according to exit polls.