(CNN) Amid all the other craziness surrounding Donald Trump's foray onto the world stage this weekend, nothing exceeded the farcical roles assumed by his daughter Ivanka Trump — who is now, like her husband Jared Kushner, a self-styled diplomat with a heavy footprint — and her brother Donald Jr., who reprised his father's racist birtherism, this time with a retweet aimed at Sen. Kamala Harris. (Then, lacking a full measure of the old man's nerve, Jr. suddenly retreated).

Although Donald Trump Jr.'s maliciousness was shocking, it was Ivanka Trump's arrogance that was truly breathtaking. Moment by moment — from the G20 at Osaka, to a jaunt into the DMZ — she inserted herself into the middle of high-level conversations, assuming the role of equal among people with vastly greater qualifications. In a sea of serious black and grays, she stood out in colorful high fashion that seemed designed to steal the limelight.

Her father's commentary about her presence — "She's going to steal the show" — betrays much truth. This is a showbiz family, treating world affairs like a performance, and in the process making the United States look ridiculous

A viral video of Ivanka Trump , who is an adviser to the President, chatting with International Monetary Fund Chief Christine Lagarde and the elected leaders of three powerful democracies — Great Britain, France and Canada — prompted commentary about her intrusion and the discomfort felt by the others.

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At one point, Lagarde, a most accomplished expert on global finance, seemed to flash a look of side-eyed impatience after Ivanka Trump chimed in in response to a comment by Theresa May, as the three stood in a group with Emmanuel Macron and Justin Trudeau. In the video, May says, in response to a comment from Macron: "As soon as you talk about the economic aspect of it, though, a lot of people start listening who wouldn't otherwise listen." Ivanka Trump offers: "It's the same with the defense side. In terms of the whole business that's been, sort of, male-dominated." She smiled eagerly and nodded at her own comment.