BATON ROUGE, La. -- It's a question that conservative Louisianans have been muttering for years: How does Democratic Sen. Mary Landrieu keep winning in a deep-red state?

For three straight elections, Republicans have scratched their heads over how they let a very winnable Senate seat slip away. They insist the fourth time will be different.

But Landrieu remains the lone statewide-elected Democrat despite never receiving more than 52 percent of the vote.

Here’s how she pulled off this feat:

Name recognition

Being a Landrieu in Louisiana has its perks.

The Louisiana senator is the daughter of former New Orleans Mayor Moon Landrieu, a legend in populist circles and revered by the black community for his stance on civil rights.

Her brother, New Orleans Mayor Mitch Landrieu, cruised to re-election last month, amassing nearly 65 percent of the vote in Louisiana’s most populous city.

The senator is not nearly so popular. As a member of a famous political family, though, Landrieu knows voters won't forget her on Election Day -- for better or worse -- and it gives her a natural fundraising edge, too.

Weak opponents

Though an impressive political force, the centrist Democrat has also been aided by some subpar competition.

For example, in 2008 Landrieu ran against state treasurer John Kennedy, who just four years earlier supported Sen. John Kerry, D-Mass., for president. Kennedy was never able to mobilize Republicans, especially in a wave election with then-Sen. Barack Obama at the top of the ticket.

In 2002, Landrieu’s main Republican opponent was a little-known elections commissioner, Suzie Terrell, who was a late entrant to the race. Even so, Terrell managed to force a runoff.

State Democrats said Landrieu learned her lesson from the closer-than-expected race, which fueled her relatively easy win six years later.

In 1996, Landrieu ran for Senate with much of the campaign structure in place from a failed bid for governor.

Aided by extensive support from then-President Bill Clinton, Landrieu ultimately bested Republican state representative Woody Jenkins in a runoff by less than half a percentage point. Analysts said that Jenkins was seen as too conservative at a time when Democrats still controlled most statewide offices.

Big turnouts in key demographics

Landrieu has always seen impressive returns in the New Orleans area, long the bedrock of Democratic support in Louisiana.

The Bayou State senator has trounced Republicans among minority voters and carried just enough support among white Democrats to squeak by in multiple elections.

But traditionally, the electorate is whiter in midterm elections, and New Orleans has seen its influence wane as its population has declined and as a growing number of Louisianans identify with the Republican Party.

Those demographic factors, coupled with President Obama’s unpopularity, are why Landrieu faces her biggest challenge in 2014.