Three months out from Election Day, political experts are hotly debating whether key groups backing Barack Obama will trigger an "Obama effect" that could propel Democratic candidates for Congress into office, while hurting their rivals.
Obama's strong appeal to certain groups of voters could help make other Democrats more competitive in traditionally Republican strongholds, particularly at a time when the GOP is suffering in nationwide polls.
Political scientist John Fortier at the American Enterprise Institute says he's skeptical that the Democratic senator from Illinois will pick up any of the South's string of red states. But Fortier and others believe that Obama's ability to draw large numbers of African-Americans out on Election Day could benefit some Democratic candidates further down the ticket.
The long, contested Democratic primaries saw African-American voter participation nationwide more than double, rising 115 percent from 2004, says David Bositis, an expert on African-American voting at the Joint Center for Political and Economic Studies. The bottom line: Obama captured 80 to 85 percent of the African-American vote in the primaries.
But the size of Obama's coattails, if any, is hard to gauge.
Take, for example, Mississippi. The Deep South state is a steep, uphill climb for Obama, even though it has, by far, the highest concentration of African-Americans in the country at 37 percent.
Unlike other places, Mississippi hasn't seen a precipitous drop in President Bush's popularity. The state has pulled the lever for a Republican in every presidential contest since Ronald Reagan in 1980.
Presumptive Republican presidential nominee John McCain, who can claim Mississippi family roots, holds a strong lead in the polls and has at his disposal a finely tuned get-out-the vote machine assembled by two-term governor Haley Barbour, former chairman of the Republican National Committee.
But even an Obama loss could herald a Democratic Party gain. If the first serious African-American contender for the presidency draws large numbers of blacks to the polls, it could shatter the Magnolia State's 20-year-old tradition of sending Republicans to the Senate.
"Because Obama is at the head of the ticket, he's going to create an awareness, and an impetus, to go and vote," says Marty Wiseman, a political scientist at Mississippi State University. "This is an opportunity African-Americans have never had before, and it may not be an opportunity they have again."
Obama's personality, Wiseman adds, "will be his own turnout machine."
In Mississippi, the race to watch is an unexpectedly close Senate contest to fill the seat recently vacated by Republican Sen. Trent Lott. On the Republican side is the new Sen. Roger Wicker, a seven-term House member until his appointment at the end of 2007 to fill Lott's seat. His opponent is Democrat Ronnie Musgrove, a former governor and lieutenant governor who lost his bid for a second term as the state's chief executive to Barbour in 2003.
"I think Republicans in Mississippi were happy to have Wicker appointed to the seat. They thought he would win election fairly easily," says Fortier. "But it turns out he is in a very, very tight race."
One wrinkle: The contest is a special election for the balance of Lott's term, which runs through 2012, and under state rules, Wicker and Musgrove will appear on the ballot without their party affiliation listed.
Voter registration in Mississippi is done without respect to party affiliation, so it's tough to gauge whether more African-Americans are signing up as Democrats. State Democratic Party officials say their primary drew a record turnout, 434,110, but comparisons to four years ago, when just under 75,000 voted, are meaningless since John Kerry had sewn up the nomination by then.
At the National Republican Senatorial Committee, spokeswoman Rebecca Fisher says, "The Obama effect could make this race a bit tougher for us, but there are a lot of unknowns." She points to Wicker's fundraising advantage (nearly $3 million cash on hand at the end of June, to Musgrove's $700,000 plus) and adds that Obama's liberal record "will energize voters against him." In the end, she says, "the Obama effect will not be the Christmas gift the Dems are counting on to win."