President Donald Trump attacked department store Nordstrom on Wednesday for dropping his daughter Ivanka Trump’s clothing and accessories line, saying that brand treated her “so unfairly.”

My daughter Ivanka has been treated so unfairly by @Nordstrom. She is a great person — always pushing me to do the right thing! Terrible! — Donald J. Trump (@realDonaldTrump) February 8, 2017

The tweet was a stunning example of Trump using his presidential bully pulpit to go after a corporation his family does business with. And it wasn’t the first time Trump took to Twitter to opine on a brand. He defended L.L. Bean last month after it took some heat because one of its board members was accused of donating money to a PAC in support of Trump.

Nordstrom’s stock appeared to take a bit of a hit around the time that the tweet was published Wednesday.

While there is nothing preventing Trump from making such statements, there are measures in place preventing those close to him from taking an interest in private businesses, including Ivanka Trump’s husband, Jared Kushner, who is also a Trump adviser, said Jordan Libowitz, communications director for Citizens For Responsibility And Ethics In Washington (CREW).

“This puts us in an area that we don’t want to be and that we don’t need to be,” he said.

Such an ethical dilemma has never happened to any other U.S. President in memory, said Libowitz.

“We’ve never seen something like this,” he said. “A year ago this kind of thing was unthinkable.”

“Even Jimmy Carter gave up his peanut farm and his peanut farm really wasn’t going to affect anything,” Libowitz added.

Nordstrom announced it was dropping Ivanka Trump’s line last week, citing poor sales and insisting that the move was not political. A spokesperson reiterated that message in a statement to TPM.

“To reiterate what we’ve already shared when asked, we made this decision based on performance,” a Nordstrom spokesperson said “Over the past year, and particularly in the last half of 2016, sales of the brand have steadily declined to the point where it didn’t make good business sense for us to continue with the line for now. We’ve had a great relationship with the Ivanka Trump team. We’ve had open conversations with them over the past year to share what we’ve seen and Ivanka was personally informed of our decision in early January.”

Trump’s business dealings have frequently caused confusion and questions about conflicts of interest. His adult male children are currently running his companies, a notable difference from a blind trust many elected officials have used in the past to stay independent from their businesses.

It’s that distinction that can make issues like this complicated, Libowitz said.

“This is where the issue of not having a blind trust becomes important,” he said. “Things like this raise concerns about whose best interest he’s working in. If he had put his businesses into a blind trust, we wouldn’t be having these issues.”

White House press secretary Sean Spicer said Wednesday in a press briefing that Nordstrom’s decision to stop carrying Ivanka Trump’s clothing and accessories line is an attack on the president’s policies and his daughter.

“There’s a targeting of her brand and it’s her name,” Spicer said. “She’s not directly running the company. It’s still her name on it. There are clearly efforts to undermine that name based on her father’s positions on particular policies that he’s taken. This is a direct attack on his policies and her name. Her because she is being maligned because they have a problem with his policies.”

Spicer also hit back on reports that Trump was in a security briefing when he sent the tweet, saying the President was “free” at the time.

Norm Eisen, chair of CREW’s board and a former White House ethics lawyer, spoke out on Twitter, saying that he would help Nordstrom and others if they considered suing Trump.

Outrageous. @nordstrom, others injured should consider suing, incl. under CA Unfair Comp Law, forbidding “any unfair biz act.” I will help! https://t.co/Y18Lml3rXk — Norm Eisen (@NormEisen) February 8, 2017

Ivanka Trump’s clothing and accessories line has generated some controversy in the past. Her jewelry line apologized last year after it promoted the bracelet she wore in a post-election interview.

In a lawsuit filed by first lady Melania Trump just this week, she said that a Daily Mail article alleging that she used to work as an escort imputed on her “unique once-in-a-lifetime” opportunity to profit from her White House role.