With her acceptance of the Democratic nomination for president, Kamala Harris simultaneously made American history and invited the nation to help her craft the next chapter of it.

In the most consequential speech of her career, Ms. Harris asked Americans to see her as the embodiment of the country’s traditional values, rather than a rejection of them. It was a message intended to reassure voters that, as much as her background and identity represent change, Ms. Harris also represents a through line to the nation’s founding ideals.

Her remarks amounted to a tacit acknowledgment that even an evolving nation may be uneasy with handing power to those who have not historically had it. And they offered an explicit counterargument against an opponent who is promising Americans a return to an idealized and insular past dominated by a white Christian male majority.

While she didn’t mention her race and gender, Ms. Harris offered an implicit understanding that some Americans may be uncomfortable with being led by a Black woman. Her approach marked a notable break with Hillary Clinton, the only other woman to capture a major party nomination, who highlighted her barrier-breaking past and possible future as a central theme of her 2016 campaign.

Ms. Harris’s speech was also a recognition that many Americans may be unfamiliar with her experience, her beliefs and her governing style — and that she was afforded less time than any other nominee in recent history to win over a fiercely divided nation.

“I know there are people of various political views watching tonight. And I want you to know, I promise to be a president for all Americans,” she said. “You can always trust me to put country before party and self. To hold sacred America’s fundamental principles, from the rule of law, to free and fair elections, to the peaceful transfer of power.”