By Martinne Geller

NEW YORK (Reuters) - First lady Michelle Obama is widely hailed as a fashion icon, but industry insiders say she's quite the opposite, and that's a good thing.

A fashion icon would have an eye-catching signature look and, while the president's wife has the power to set trends, her appeal is refreshingly not so defined and deliberate, said fashion observers at the semi-annual Fashion Week in New York, where designers are showing their Fall 2009 collections.

Michelle Obama "is more real than iconic," said David Wolfe, creative director of the Doneger Group, which forecasts trends. "She doesn't have a locked-in fashion look. She experiments, which is what fashion is about these days."

References to Obama, 45, as an icon of fashion are everywhere. Thin and statuesque, the attorney and mother of two graces the cover of Vogue magazine's March issue.

She wins lavish attention from designers, editors and stylists. Stores quickly sell out of the clothes she wears.

While Obama's style merits praise, she is not in the ranks of such icons as actress Katharine Hepburn, with her tailored menswear, or Jacqueline Kennedy with her pillbox hats and wide-frame sunglasses, said Helen Job, a trend forecaster with WGSN, a fashion research and analysis firm.

"When you think about a fashion icon, it's somebody who has this ability to influence the public to such a degree ... to change the direction (a style) is going in," she said.

Kennedy's sense of style would be out of place among women today, said Wolfe.

"Jackie Kennedy was locked into the Jackie Kennedy look and never stepped out of it. That was great, but it certainly isn't the way modern women dress," he said.

Obama wears clothes by little-known designers and mid-priced chains such as J Crew Group Inc, helping dispose of the idea that first ladies always must look formal.

"She's really set this new guideline, and I feel like the White House will never be the same after this somehow," said Gloria Baume, fashion director for Teen Vogue.

DEMOCRATIC FASHION

Jason Wu, the young designer of Obama's white inaugural gown and the magenta dress she wears in Vogue, credits the first lady with reinvigorating the industry.

"In her own way, she is like a stimulus package for the fashion industry," Wu said.

Few first ladies deserved the title as fashion icons, said Mandi Norwood, a former magazine editor writing a book on Obama's style.

"We've been trying desperately to promote the first lady into fashion icon status, but I'm not sure any of them have truly deserved that title," she said.

Obama does have some company in U.S. history, said Lisa Kathleen Graddy, curator of "The First Ladies at the Smithsonian" exhibit.

Frances Cleveland's clothes and hairstyle were copied and commented upon, and advertisers used her to sell products she had never seen or used. The Victorian-era bustle even fell out of U.S. fashion when it was reported she would no longer wear the rear-enhancing gowns.

Another fashionable first lady was Grace Coolidge, who is considered to have popularized fashion, said Graddy.

Grover Cleveland was president in the late 1800s. Calvin Coolidge served in the 1920s.

(Additional reporting by Christine Kearney in New York and Alexandria Sage in San Francisco; editing by Ellen Wulfhorst and Philip Barbara)