Neil Gorsuch gave a speech at the Trump International Hotel - and it sparked an uproar

Supreme Court Justice Neil Gorsuch sparked an uproar this week by accepting an invitation to speak at a conservative event held at the Washington, DC-based Trump International Hotel, in which the president still holds a financial stake.

Dozens of protesters descended on the hotel on Thursday ahead of Gorsuch's speech, carrying signs with messages like "Gor$uch for sale" and chanting, "Who is Gorsuch? Such a sellout," Politico reported.

Organizers of the event appeared baffled by the controversy, and told media they had booked the hotel before Trump was elected president and Gorsuch was nominated to the Supreme Court.

"We had no political agenda, it's just a nice hotel and a new venue for us," Steve Slattery, spokesman for the conservative Fund for American Studies, told CNN.

But ethics watchdogs, too, cried foul over the speech and questioned whether Gorsuch's appearance compromised his impartiality - particularly if certain lawsuits against Trump and his businesses eventually make their way to the Supreme Court.

"He's helping a conservative organization put money into the pockets of the president who put him on the bench. And that doesn't really give a strong sense of independence from that president," Elizabeth Wydra, president of the nonprofit think tank the Constitutional Accountability Center, told NPR.

"You have the Trump hotel at the center of at least three lawsuits filed against President Trump for violating the Constitution's Foreign Emoluments Clause … It's certainly not a good look."

The left-leaning Constitutional Accountability Center is representing more than 200 members of Congress in their lawsuit against Trump over the emoluments clause, the constitutional provision prohibiting government officials from receiving payments from foreign governments.

That clause had not previously been tested in court against a US president - yet there are now reportedly at least five lawsuits pending in federal courts across the country that claim Trump's failure to fully divest from his businesses violate the emoluments clause.

Gorsuch in his speech did not address the criticisms his appearance had sparked, nor did he refer to Trump's ownership of the hotel, according to Politico. Instead, he spoke about free-speech rights and civility.

"Those with whom we disagree vehemently still have the best interests of the country at heart," Gorsuch said. "We have to learn not only to tolerate different points of view, but to cherish the din of democracy … It's not just about good manners and courtesy. It's about keeping our republic."

He continued: "To be worthy of our First Amendment freedoms, we have to all adopt certain civil habits that enable others to enjoy them as well."

Although Gorsuch stipulated that the speech not be used to solicit donations, and he was not paid for his appearance, profits from the event will go to the Trump hotel, and even Trump himself. The president has moved his assets to a trust in his name, meaning he can still profit from his businesses, albeit after he leaves office.

"To the public the Trump Hotel appears simply as what it is: a paid gateway to presidential influence that operates under the color of presidential approval," a group of officials from liberal organizations such as People for the American Way, Naral, and Planned Parenthood wrote in a letter to Chief Justice John Roberts, urging the court to address the incident.

"Justice Gorsuch, in accepting an invitation to keynote an event, shows disregard for the Court's ethical standards and traditions, for its sacred reputation, and, bluntly, for basic common sense."