The nation will be watching Barack Obama Tuesday as he is sworn in as the 44th president. But millions of Americans will also be gazing at his wife, Michelle, and giving a thumbs up or down. For her style.

The new first lady will be either copied or criticized, no matter the color, cut or price tag of her clothes. But the ball gowns, jewelry, shoes and purses of each first lady also represent the never-ending changes in American fashion — and Americans' fascination with it.

Just down the National Mall from the Capitol where Michelle Obama will watch as her husband takes the oath of office is the National Museum of American History at the Smithsonian. One of its most popular attractions is the First Ladies Collection that displays clothing and accessories, personal possessions, china and portraits of first ladies from Martha Washington to Laura Bush.

Just last month, the museum opened a new expanded exhibition that will serve as a bridge to an even larger exhibition set to open in a few years.

"The original first ladies exhibition of 1914 was the first at the Smithsonian to prominently feature women," museum director Brent D. Glass said. "Today we continue to delve deeper into the contributions of first ladies to the presidency and American Society."

The first item donated to the collection was the 1909 inaugural gown of Helen Taft, a white-silk chiffon gown, which was appliqued with floral embroideries in metallic thread and trimmed with rhinestones and beads.

The last donated gown was Laura Bush's red Chantilly lace and silk satin dress with crystal beading that she wore in 2001.

Among more than 1,000 objects in the First Ladies Collection is the pink-rayon crepe gown worn by Eleanor Roosevelt to a 1945 inaugural reception. The reception was held in lieu of a ball during World War II.

In the roarin' '20s Grace Coolidge wore flapper-style evening dress of velvet-trimmed black-and-gold metallic lace over a gold lam?undress.

Rosalyn Carter was criticized for her inaugural ball attire in 1977 — because she wore the same dress that she had worn six years earlier when Jimmy Carter became governor of Georgia. It was a blue chiffon evening gown and sleeveless coat trimmed with gold embroidery and braid.

And one thing is almost certain, whatever Michelle Obama wears Tuesday will end up in a museum.

E-mail: angie@desnews.com