Michelle Obama, the wife of presumptive Democratic presidential nominee Sen. Barack Obama (Ill.), struck an aggressive tone toward Republicans this morning, saying the country must do more to help women struggling to make ends meet.

Michelle Obama, appearing at a women’s economic forum with Sen. Joseph Biden (D-Del.), her husband’s vice-presidential pick, and several female governors, urged an audience of largely female Democrats to “think about the stakes” this fall and the contrast between the two parties on women’s issues. Her remarks were a noticeable contrast to her convention address Monday night — which was a largely positive one focused on her autobiography.

“Although we are blessed and we are proud of this nation, we should do better,” she said, listing several issues that would be a priority for her husband’s administration, including pay equality, expanded medical leave and universal health care by the end of his first term.

Michelle Obama chided Republicans, saying “instead of just talking about family values, we actually have policies that value your families.”

Biden, a former chairman of the Senate Judiciary Committee, reminded the audience of the role he played in defeating past conservative court nominees. Aside from the Iraq War, Biden said, the single most important issue facing Barack Obama as president would be picking as many as three Supreme Court justices.

Biden accused President Bush of naming to the Supreme Court “ideologues” who want to “change the way most Americans want to run their lives.”

Arizona Gov. Janet Napolitano (D) took aim at her state’s senior Senator, saying presumptive Republican nominee Sen. John McCain was on the wrong side of the issue on pay equality and ending the Iraq War. In a poke at recent reports that McCain owns multiple homes, Napolitano said that most Arizonians own one home and that she lives in a condominium because her state does not even have a governor’s mansion.

Michelle Obama noted the early backing of Napolitano and other female governors during the primary season, saying they “really have been taking it on the chin” for supporting her husband.