Donald J. Trump was discussing his dynasty.

It was last Tuesday, before a would-be assassin’s bullet sliced through his ear, and he was surrounded by his family onstage at a rally at his golf resort in Doral, Fla. One by one, he shouted out his grandkids and his three sons: Don Jr. (“very tough”), Eric (“somebody who’s fantastic”) and Barron (“he might be more popular than Don and Eric!”).

Then the former president mentioned one family member who was not there that day.

“You like Lara, right?” he asked the crowd, sounding like a salesman at a product launch. “Lara is only the head of the Republican Party,” he said of Eric’s wife. “She’s upwardly mobile.”

Lara Trump’s rapid ascent — from apolitical tabloid television producer to party boss — is on full display this week as Republicans convene in Milwaukee to nominate Mr. Trump. As the party’s co-chair, she is also the host of this four-day Trump-fest. On Monday, she sat directly behind her father-in-law as he made his emotional first appearance since the assassination attempt. On Tuesday, she is scheduled to address delegates for nearly 15 minutes, longer than elected officials like Kristi Noem, Glenn Youngkin or even Marjorie Taylor Greene were given onstage.

This is probably what Mr. Trump had in mind when he pushed her to take the job in March. In the time since, Ms. Trump, 41, has become one of the campaign’s most visible defenders in the media, putting a smiling spin on some of the darkest aspects of her father-in-law’s campaign for the White House.

But with great airtime comes great risk — at least in Mr. Trump’s orbit. Aides who fail to execute his vision can get tossed aside; some who succeed have ended up indicted. Ms. Trump acknowledges the unusual, dual pressures of being both operative and in-law. If Mr. Trump wants her help subverting an election, what would she do?

“The ante’s been upped in a lot of ways,” she said when asked in an interview with The New York Times last week.