By Rachel Kapochunas, CQ Staff

Barack Obama defeated Hillary Rodham Clinton in Mississippi’s Democratic presidential primary Tuesday, dominating among African-American voters in a state where that constituency accounts for roughly half the party’s electorate.

Yet Obama’s widely expected win added only incrementally to his lead over Clinton in the all-important count of delegates to the Democratic National Convention. Of the 40 delegates apportioned to Mississippi, 33 are pledged delegates who will be divided between the candidates in proportion to their percentages of the primary vote. The remaining seven are unpledged party leaders and elected officials known as “superdelegates.”

According to the Associated Press, Obama had 1,562 delegates going into Tuesday’s primary to Clinton’s tally of 1,461. A total of 2,025 delegates are needed to clinch the nomination.

Both campaigns are looking ahead to the Pennsylvania primary April 22, the next major event in the nominating campaign, in which 188 Democratic delegates are up for grabs. Obama, whose chances for an early knockout of Clinton were scuttled by her March 4 wins in the Ohio and Texas primaries, will claim renewed momentum from the Mississippi win, coming on the heels of his victory in the Wyoming caucuses held March 8.

But Clinton’s campaign played the expectations game leading up to the Mississippi primary, essentially conceding the contest to Obama. Clinton made no major announcements, with campaign manager Maggie Williams issuing a terse written statement: “We congratulate Sen. Obama for his win in Mississippi and thank our supporters and volunteers there for their support, hard work and long hours. Now we look forward to campaigning in Pennsylvania and around the country as this campaign continues.”

Obama was declared the winner by major national news outlets based on a big lead in exit poll results. In the actual vote count, Obama led with 60 percent of the vote to 37 percent for Clinton with 99 percent of precincts reporting.

Obama, speaking from his home city of Chicago, characterized his victory as “another win in our column” during a live television interview one hour after the polls closed.

“I am grateful to the people of Mississippi for the wonderful support,” Obama told CNN. “What we’ve tried to do is steadily make sure that in each state we are making the case about the need for change in this country, and obviously the people of Mississippi responded.”

Obama also took the opportunity to obliquely criticize the recent tone of Clinton’s campaign, in which the former first lady and New York senator has strongly suggested that first-term Illinois Sen. Obama is too inexperienced and unprepared to handle the presidency, especially when it comes to national security issues.

Obama said his campaign has been “very measured” in its comments about Clinton. “I’ve been careful to say that I think Sen. Clinton is a capable person and that should she win the nomination, obviously I would support her,” Obama said. “I’m not sure that we’ve been getting that same approach from the Clinton campaign.”

Exit polls showed a pronounced racial divide, though Obama gained more support among white voters than Clinton did among African-Americans.

According to exit poll figures posted on CNN’s Web site, Obama received support from 90 percent of black Democrats who responded to the poll. Clinton was favored by 74 percent of white Democrats (who made up 24 percent of the respondents) and 59 percent of white independents (13 percent of the total) who were allowed to vote in the state’s open primary.

Clinton’s husband, former President Bill Clinton, had strong ties to the African-American constituency from his White House tenure and he spent time campaigning for her in Mississippi. But some African-Americans expressed offense at comments made by the former president after Obama’s victory in the South Carolina primary Jan. 26, in which Clinton compared Obama’s win to black activist Jesse Jackson’s success in the state when he ran for the Democratic presidential nomination in the 1980s.

Both Clintons have generally avoided racial implications recently, but the issue emerged again as the result of comments made to a newspaper by Clinton campaign adviser Geraldine Ferraro. The former New York congresswoman — who in 1984 made history by running for vice president on the Democratic ticket headed by Walter F. Mondale — recently told the Los Angeles-area Daily Breeze newspaper: “If Obama was a white man, he would not be in this position.” She continued, “And if he was a woman (of any color), he would not be in this position. He happens to be very lucky to be who he is. And the country is caught up in the concept.”

Obama’s campaign called on Clinton to reject the comments. Clinton’s campaign released a statement Tuesday noting that Clinton had stated, “I do not agree with that and you know it’s regrettable that any of our supporters on both sides say things that veer off into the personal. We ought to keep this focused on the issues. That’s what this campaign should be about.”

Exit polling also suggested that the economy was the most important issue for Democratic primary voters, placing well ahead of health care and Iraq among voters’ top priorities.

There were a couple of interesting twists in the exit polls. Previously, Obama had done well among Republicans who chose to vote in open Democratic primaries but in Mississippi, exit polls indicated Clinton took 79 percent among Republicans who voted Democratic, a group that made up 13 percent of the respondents.

Many of Clinton’s wins have been powered by support among less affluent voters. But black voters in Mississippi, who as a group have below-average incomes, flipped that equation. Obama ran best among the lowest-income voters in Mississippi, while Clinton held a modest lead among the wealthier voters.

Republicans also held their presidential primary Tuesday, though it was stripped of suspense by the fact that Arizona Sen. John McCain essentially clinched the party’s nomination last week. McCain ran away with the primary with 79 percent of the vote to 12 percent for former Arkansas Gov. Mike Huckabee , who ended his campaign last week.

The lack of a competitive Republican contest reinforced one of the most consistent trends of the presidential nominating campaign: a huge advantage for the Democratic Party in voter turnout. Although Mississippi is generally a Republican stronghold that gives GOP presidential candidates big general election margins, turnout for Tuesday’s Democratic primary was nearly triple that for the Republican primary: 407,217 votes recorded in the Democratic contest to 140,427 in the GOP contest with 98 percent of precincts reporting.

Voters in both party primaries also cast ballots Tuesday in the state’s congressional primary elections.