By Kevin Liptak , Jeff Zeleny and Priscilla Alvarez , CNN As advisers to Vice President Kamala Harris were mulling where to stage the final major address of her campaign, they had a few boxes to check. The venue, they believed, must convey a degree of gravity about the choice before voters. But equally important, in their view, was its ability to evoke the promise of the office she seeks.

In the Ellipse - the patch of park where Donald Trump rallied his supporters on 6 January 2021, within view of the White House - they believe they found that equilibrium. For Harris, striking a balance between dire warnings about a rival she calls a fascist and forward-looking optimism about the president she would be has become a defining challenge of the campaign's closing stretch. Tuesday's (local time) high-profile speech is one of the last remaining opportunities for the vice president to try to reach a critical segment of the electorate known inside the campaign as "conflicted voters," aides said, or those who may have concerns with Trump's conduct but who are not yet convinced Harris is a candidate of change who can get the country on track.

While it's hard to imagine that one speech could move the needle, aides said, it is also intended to draw a clear contrast with Trump's controversial Madison Square Garden rally Sunday evening. That was not the original intent of Harris' major address, aides said, but they believe it serves as a timely rebuttal. "It's going to crystallize many of .