Analysts viewed Landrieu's narrow 52-48 percent win as a sign that moderate Democrats are holding their own in the South despite Republican gains in recent years in both state and national offices.
The theory gained strength with another runoff election, in Louisiana's 5th Congressional district, where Democrat Rodney Alexander defeated Lee Fletcher in a bid for the House seat vacated earlier this year by Republican John Cooksey. Fletcher, a former aide to Cooksey, lost the race by just 518 votes.
In the Senate race, the Republicans pulled out the stops in their effort to defeat Landrieu, sending their heaviest hitters to the state to campaign for Terrell.
While the Republicans achieved a 51-49 Senate majority in the elections held in early November, the party hoped to bolster its position by claiming the seat left undecided when Landrieu failed to win more than 50 percent of the vote in Louisiana's Nov. 5 open primary, which pitted her against eight other candidates and forced her into the runoff with Terrell.
Landrieu's primary national political support came from fellow Sen. John Breaux, D-La., who is serving his third term in the Senate and who campaigned side-by-side with the candidate across the state in recent weeks.
Landrieu, whose father, Moon Landrieu, was mayor of New Orleans in the 1970s and whose brother, Mitch, is a state representative, won her Senate seat in 1996.
Emerging from the November primary with 46 percent of the vote to Terrell's 27 percent, Landrieu faced a heavy assault by conservative critics who painted her as an ultra-liberal Democrat who supported abortion on demand and higher taxes.
In her victory speech Saturday night, Landrieu made reference to the attacks.
"People can see the dangers of partisan, poison politics," she said. "People know in their hearts that a campaign should strengthen us and make us better, not weaken us."
New Orleans political analyst Clancy Dubos thinks the personal attacks on Landrieu ended up backfiring on Republicans. Noting that the television and radio attacks continued into the final hours of the campaign, Dubos said, "The Republican attack strategy was a brilliant strategy, but they didn't know when to turn it off."
Landrieu focused much of her get-out-the-vote efforts on African-Americans, who historically have voted overwhelmingly for Democrats in Louisiana. While she steered clear of associations with national Democratic leaders throughout her campaign, some voters received an Election Day automated telephone call from former President Bill Clinton urging them to the polls.
Morial speculated Saturday night that voters around the state, and particularly in New Orleans where Landrieu grew up and much of her large family still lives, were turned off by the Republican attacks on her.
"The barrage of negative campaigning may have turned some voters off," Morial said. "The dollars put behind the totally negative campaigning on (Terrell's) behalf is something the likes of which I've never seen."
Morial also suggested that Terrell, also from New Orleans, may have been hurt indirectly by top-heavy support from the Republican Party.
"To some extent, when the president came in, Suzie was put in a position where she had to defend the president on issues like steel and sugar (imports)," he said.
In the final week of campaigning, Landrieu focused on the issue of Mexican sugar imports and their impact on Louisiana sugar cane growers. She said Terrell would be a "rubber stamp" for Bush and accused Terrell of quietly supporting the White House in a "secret deal" that will double the flow of sugar coming from Mexico. Terrell claimed no such deal exists.
Landrieu also warned that Louisiana would lose her economically important seat on the Senate Appropriations Committee if Terrell should prevail.
Reports show that Landrieu and the Democrats spent $6 million in the campaign compared to $5 million by Terrell and the Republicans.
In the waning days of the campaign, speculation arose that if Terrell should lose the Senate race, her next likely step would be a run for governor of Louisiana. During her concession speech at campaign headquarters Saturday night, a supporter briefly interrupted her with a shout of "Terrell for governor." Terrell smiled broadly but did not comment.