It only makes sense that such an unprecedented president-elect should have an unprecedented First Daughter. And to Donald Trump, Ivanka has long been first among equals.

Of his five children, she is peerless. During a family interview with Barbara Walters last year, Eric, Donald Jr. and Tiffany Trump all said Ivanka, 35, is their father’s favorite. When asked, years ago, how he ranked Ivanka and his other daughter Tiffany, Trump said there was no contest.

“Come on!” he said. “Daddy’s little girl!”

While the media has, as it should, assiduously reported on every official Cabinet appointment made by President-elect Trump, they have yet to vet the next administration’s most significant, powerful player: Ivanka. She’s not the first woman to sub for a first lady — most notably, Teddy Roosevelt’s daughter Alice did — but none had the influence Ivanka likely will.

Forget adviser: Ivanka, now moving her family to DC, may be co-president.

“The only phone call Donald would always take,” a Trump insider told Politico last July, “was Ivanka.”

Last week, Trump’s team floated Ivanka as inhabitant of the First Lady’s office in the East Wing. Ivanka also began personally lobbying Congress on child-care legislation.

Even if Trump’s wife, Melania, hadn’t announced that she’d be staying behind in New York City to see their 10-year-old son, Barron, through the end of the school year, the campaign itself proved that Ivanka’s opinions and advice, her branding and image, were prized most highly by Donald.

It was she, not Melania, who introduced the candidate at the Republican National Convention. In her speech, Ivanka sanded down the image of her father as a grotesquerie who rates women on a scale of 1 to 10, who has traded in wife after wife for younger, hotter models, who once boasted that Ivanka herself was so hot that, if not for biology, he’d be dating her.

“At my father’s company, there are more female than male executives,” Ivanka said. “Women are paid equally for the work that we do and when a woman becomes a mother, she is supported, not shut out.”