Back in 2005, Reese Witherspoon was a top star; she was earning $15 million a picture, was a reliable box office draw in romantic comedies, and proved her mettle as a dramatic actress by winning an Oscar for "Walk the Line." Today, she's a performer whose last $100-million hit was four years ago, who starred in one of Hollywood's costliest recent flops, and whose current romantic comedy (20th Century Fox's "This Means War") suffered a last-minute release date change, away from its initially scheduled Feb. 14th premiere, apparently because she wasn't a big enough draw for Valentine's Day date-night audiences. Yet she's still earning a reported $15 million per picture. Which raises the question: how does Witherspoon manage to remain an A-list star, in demand for leading roles in big-studio movies, even as her box office drawing power has waned?

Last fall, Forbes ranked Witherspoon fourth on its annual Most Overpaid Actors list; according to the magazine, only Drew Barrymore, Eddie Murphy, and Will Ferrell offered Hollywood producers a lower return on investment. The chief reason: the high-profile failure of her 2009 romantic comedy "How Do You Know," which cost $120 million to make but returned only $30 million at the domestic box office. Before that, her last big hit was 2008's "Four Christmases." That comedy earned $120 million, but arguably, at least half the credit could be attributed to her co-star, Vince Vaughn. Otherwise, her record since 2005 includes the flops "Rendition" and "Penelope" (both of which topped out around $10 million in the U.S.) and the modest success "Water for Elephants," which cost $38 million and earned back $57 million in North America.

"This Means War" which sees spies Chris Pine and Tom Hardy sabotaging each other as rivals for Witherspoon's affections, looks on paper like the kind of romantic comedy that drew ticketbuyers back in the days of such Witherspoon hits as "Sweet Home Alabama" and "Just Like Heaven." Actually, however, it's more of an action comedy, about guys blowing stuff up, with a romance angle to it, a la "Mr. and Mrs. Smith" (which shares a screenwriter, Simon Kinberg, with "This Means War.") So it's far from a traditional Valentine's Day movie, despite the way it's been marketed. No wonder Fox decided to move it away from Feb. 14, where it would have competed against the newly-opened "The Vow," a more traditional, tearjerking romance starring Rachel McAdams, who is practically a sure thing at the box office in that kind of movie.

Also confusing: Witherspoon's apparent effort to create a sexier image for herself. After more than a decade in America's Sweetheart roles, she's now in a movie where two hunky guys are literally battling over the opportunity to date her. She's also showing up at the movie's premieres in low-cut dresses that show off a lot of cleavage. But audiences aren't used to thinking of her that way. Notes a marketing consultant from a studio unaffiliated with the movie, talking to New York magazine's Vulture blog: "She’s not that type of girl. Reese Witherspoon is the modern Doris Day: She’s the girl you marry after the hot chick has moved on to the next guy."

Finally, the fact that Witherspoon doesn't make as many movies as some of her peers has also dimmed her luster, as she's seldom out in public promoting herself. "Reese Witherspoon’s career has definitely tapered off compared to a decade ago when she was the 'it-girl' in Tinseltown," says Jeff Bock, senior box office analyst at Exhibitor Relations Co. "She is a rare commodity in Hollywood that seems to choose family over fame, as she routinely only does a single film per year. No doubt that has been part of what has cooled off her star status, but there is no doubt one hit could amp her wattage back to where it was previously."

Making only one movie per year, Witherspoon needs to choose her projects especially carefully. "I think Reese Witherspoon is still a bankable actress, but it depends on how commercial the project is in the first place," says Gitesh Pandya, editor of Box Office Guru. "'Four Christmases' performed very well a few years ago putting her with a big male co-star in a broad adult couples comedy released over the busy Thanksgiving holiday. Put her into a war movie about the Middle East [like 'Rendition'], and theaters will be empty."

Witherspoon's continued ability to command top-dollar fees for high profile projects recalls other A-list actresses who were able to do the same, even after they were no longer hitmakers. Throughout the 1990s, Winona Ryder continued to land high-profile leading roles long after her last blockbuster (1992's "Bram Stoker's Dracula"). In the last decade, Nicole Kidman continued to be in demand for top parts for nearly 10 years after her last smash (2001's "The Others"). Of course, it helped that these women (like Witherspoon) had talent and beauty. They also had tabloid notoriety, which can be a double-edged sword. Ryder spent the '90s enjoying well-publicized romances with famous actors and musicians, but the fallout from her shoplifting bust seemed to halt her career in its tracks. In Kidman's case, she rode for years on the fascination over her 2001 split from Tom Cruise, but studio interest in her seemed to wane once she settled down with Keith Urban in Nashville, far from the Hollywood paparazzi. Both actresses attempted comebacks by taking supporting roles in Adam Sandler comedies ("Mr. Deeds" for Ryder, "Just Go With It" for Kidman).

Witherspoon had her own entanglement with the tabloids during her split with Ryan Phillippe in 2006, coinciding with the start of her decline as a box office draw. These days, she's remarried (to her agent, Jim Toth) and is no longer a subject for gossip, except for her fashion choices. At least she already got her Sandler cameo out of her system when she was on her way up, in 1999's "Little Nicky."

Ultimately, for Witherspoon and actresses like her, talent can keep them on the A-list, but so can Hollywood inertia. Casting directors would rather go with a name, even a tainted name, than with someone new and untried. Says Bock, "I think that in the case of Reese and Nicole, they are both extremely talented actresses, and that really does go a long way in terms of career longevity. Truth is, once you’ve had huge success, and then lost it, there is always the mindset that the next project could re-launch their career. Name recognition is a huge draw for studios in terms of advertising their products, so having a lead actress that people are familiar with is essential for a studio vehicle."

Bock adds, "Once you’re on the elusive A-list, you are offered top-tier scripts from top-tier talent. Plus, they are definitely allowed a few more flops, as long as they produce a hit every few years. And that’s really the prime perk of being on Hollywood’s A-list."