On Saturday, a Russian official photographed Ivanka Trump sitting in her father’s seat at the G20 Summit in Hamburg, Germany. Ivanka’s visibility at the annual meeting of world leaders ruffled so many feathers it got a rise out of our nation’s temperamental leader.

On Monday morning, Trump took to Twitter to defend Ivanka as his stand-in. But instead of addressing the viability of using his daughter as a proxy, he issued a torrent of hostile tweets, a sizeable amount of which were retweets from a Fox & Friends. In one tweet, Trump namedrops German Chancellor Angela Merkel: “When I left Conference Room for short meetings with Japan and other countries, I asked Ivanka to hold seat. Very standard. Angela M agrees!” he wrote. Merkel backed him up, telling reporters, “The delegations themselves decide, should the president not be present for a meeting, who will take the chair, and Ivanka Trump was part of the American delegation,“ she said. “It is very well known that she works at the White House and that she is engaged in certain initiatives.”

As unprofessional as it’s written, Trump’s defense does have merit. United Kingdom Prime Minister Theresa May’s aide briefly took her place at G20, and nobody took issue with that. According to the Agency France-Presse, a White House official said that “When other leaders stepped out, their seats were also briefly filled by others.”

So, as often is the case, it was Trump’s reaction that fueled critics’ fire—primarily because of his erratic attack on Hillary Clinton and her daughter, Chelsea. Trump claims that if Hillary Clinton was president and Chelsea held her seat for her, she would have been treated dichotomously. He wrote, “If Chelsea Clinton were asked to hold the seat for her mother,as her mother gave our country away, the Fake News would say CHELSEA FOR PRES!”

Because he is his father’s son, Donald Trump Jr. jumped in on the action. “You can belittle her all you want w your snark, but we all know 1 on 1 she way out of your league,” he said in response to political commentator Ana Navarro.

He followed his comment with, “If the left is so ‘outraged’ about Ivanka sitting in for a few minutes, maybe they’d be happier if I sub in for a while??? LMK.”

Not long after, Chelsea Clinton responded to Trump’s mention. “Good morning Mr. President. It would never have occurred to my mother or my father to ask me. Were you giving our country away? Hoping not,” she said.

Because everybody loves to hate Trump, many were quick to compliment Clinton’s classy yet jagged rebuttal.

Way to take the high road, Chelsea. And shame on you, Donald Jr. You’re almost 40 years old, for crying out loud.