In Chicago, Biden and Harris Enact a Cast Change Onstage

Notice anything different?

The organizers of the Democratic National Convention hope you did. Less than a month ago, the party upended the election when President Biden withdrew from the campaign, and Kamala Harris became the presumptive nominee. Suddenly, the previously scheduled rerun of the 2020 election, tuned out by many weary voters, was new programming, with a new cast.

The first night of the convention wasted little time unveiling its new star — even as it also had to finish off the last one’s story arc.

Early in the evening, Ms. Harris made a surprise appearance onstage in Chicago to her campaign anthem, Beyoncé’s “Freedom.” The crowd of delegates exploded with cheers.

This was an energy that the party had been missing for a while, and the prime-time production was designed to flaunt it. Ms. Harris’s kickoff remarks were brief — “We are moving forward!” — but there was a showmanship to the moment that suggested that the candidate plans to take the fight to Donald Trump where he lives, in the TV lights.

If Ms. Harris’s unexpected cameo had a measure of Mr. Trump’s theatricality, however, it had a different energy: expansive and effusive rather than brassy and bold. Beaming and waving to the crowd in a camel-colored suit, she reflected the room’s energy back to it rather than basking in it and soaking it up.

This was a big change from the convention Democrats anticipated having just weeks ago, under the tentative, 81-year-old Mr. Biden. The slogans onstage — “For the People, For the Future” — emphasized the message of newness.