Harris, Needling Trump, Holds a Rally at His Convention Site

Vice President Kamala Harris will hold a rally in Milwaukee on Tuesday night at the same basketball arena where former President Donald J. Trump accepted the Republican nomination just a month ago, at a time when his party believed he was coasting to victory against a hapless President Biden.

Ms. Harris’s choice of venue is the latest in a series of aggressive moves that seem designed to get under Mr. Trump’s notoriously thin skin.

Crowd size is one of the former president’s most reliable bugbears. Ever since 2016 — when his huge rallies seemed to foretell his unexpected victory against Hillary Clinton — Mr. Trump has been obsessed with how many people show up to hear him speak and how many come to hear his opponents.

If Ms. Harris is able to fill up Fiserv Forum’s roughly 18,000 seats, it could ignite another angry reaction from Mr. Trump. He has already falsely accused the Harris campaign of using artificial intelligence to generate fake images of her crowd at a rally in Detroit. And he has also claimed, again without evidence, that his rally in Washington on Jan. 6, 2021, drew more people than the Rev. Dr. Martin Luther King Jr.’s “I Have a Dream” speech — bringing more attention to his role in the assault on the Capitol that happened later that day.

Ms. Harris has reshaped the race since replacing Mr. Biden on top of the ticket last month, raising hundreds of millions of dollars, generating a wave of enthusiasm from rank-and-file Democrats and narrowing the gap or even taking the lead against Mr. Trump in many polls of battleground states, including Wisconsin.

“Donald Trump is perhaps the most thin-skinned person ever to run for president,” said Representative Brendan Boyle, a Democrat from Pennsylvania. “So he’s fairly