Back then, as she wrestled uncomfortably in competing against the man who would become the first black president, Mrs. Clinton appeared reluctant to make race a central issue. And her husband, former President Bill Clinton, angered many African-American leaders with off-the-cuff comments that seemed to diminish Mr. Obama’s stature, including calling his antiwar position “the biggest fairy tale I’ve ever seen.”

Now, Mrs. Clinton is offering sweeping and passionate speeches on race, which was one of the subjects that first drove her interest in politics in the 1960s and ’70s.

On Tuesday, she will hold a community meeting at a black church in Florissant, Mo., near Ferguson, where clashes between black protesters and police officers erupted last summer after an unarmed African-American teenager was killed by a white police officer. At the meeting, she plans to discuss the massacre of nine people last week at a black church in Charleston, S.C., and “broader issues around strengthening communities,” her campaign said.

On her Twitter account on Monday, Mrs. Clinton restated her belief that South Carolina should stop flying the Confederate flag on the grounds of its State House.