Continued from page 1

But behind the scenes, she’s a sounding board for her husband on pressing policy matters. She also has increasingly promoted his health care overhaul after it was upheld by the Supreme Court.

Aides say she will sprinkle her remarks Tuesday with a defense of the president’s policies, including the health care law and the Lilly Ledbetter Fair Pay Act, which was the first legislation Obama signed into law. The act makes it easier for women to sue for equal pay if they earn less than their male counterparts. Obama has made the law a key part of his election-year appeal to women, who could give him an edge over Romney in a tight race.

The first lady arrived in Charlotte on Monday and informally rehearsed at the Time Warner Cable Arena. She also taped interviews for entertainment programs that will air before her speech.

Mrs. Obama is staying in Charlotte during the three-day convention and will focus on shoring up support for her husband among key constituencies. She plans to speak to the party’s African-American, Hispanic and women’s caucuses and address a gay and lesbian luncheon. Along with the vice president’s wife, Jill Biden, the first lady will also participate in an armed services event Thursday and put together care packages for U.S. troops serving overseas.

Mrs. Obama will join a crowd of up to 74,000 people at an outdoor football stadium on Thursday night when the president formally accepts the Democratic nomination. The first lady is not expected to have a speaking role that night, but she, and possibly her young daughters, will join the president on stage, leaving voters with fresh images of the photogenic family.