“The Court will not issue an Order requiring the production of the depositions of Mr. Steele and Mr. Kramer,” wrote Magistrate Judge John J. O’Sullivan. He was referring to David Kramer, a former confidant of Senator John McCain who met with Steele in 2016 to discuss the dossier’s allegations and was deposed as part of the same lawsuit earlier this year. O’Sullivan ruled that both committees would have to move forward in formal channels and “advise the court why it would be appropriate to require the production of these depositions.”

Gurvits and Grassley did not return requests for comment.

Donald Trump’s relentless assault on Special Counsel Robert Mueller’s investigation into possible collusion between his 2016 campaign and the Russians begins with the Steele dossier, which the president and congressional Republicans consider the probe’s proximate cause.

In fact, the dossier did not trigger the probe. The investigation began before the bureau obtained the document, when George Papadopoulos, a Trump campaign adviser, told an Australian diplomat in May 2016 that Russia had dirt on Hillary Clinton in the form of thousands of emails, The New York Times has reported. The dossier concluded that Russian President Vladimir Putin himself had directed a long-standing Russian-intelligence operation aimed at compromising Trump and supporting his 2016 presidential campaign by hacking and dumping unflattering information about Clinton.

With Wednesday’s order in Florida, O’Sullivan introduced an additional check on the Republicans’ ability to pursue additional information about Steele and his sources. Grassley, for his part, has made examining Steele and the firm that hired him to examine Trump’s Russia ties, Fusion GPS, a priority. In March 2017, the Iowa Republican and Trump ally accused Fusion of failing to register as a foreign agent due to work the firm did that benefited a Russian company. (The complaint ultimately went nowhere, since Fusion was technically working for an American law firm that represented a Russian client, and was therefore not required to register the work with the Department of Justice.)

Nearly a year later, Grassley and Republican Senator Lindsey Graham issued a criminal referral of Steele to the Justice Department, urging the DOJ to examine whether Steele had made false statements to the FBI about his interactions with the press in late 2016. The referral was broadly perceived as a political stunt—Grassley and Graham were not giving the Justice Department, which oversees the FBI, information about Steele that it did not already have—and nothing came of it.

Just last month, Devin Nunes, the chairman of the House Intelligence Committee, went to London seeking new information about Steele. But sources familiar with his trip told me that officials at MI6, MI5, and Government Communications Headquarters were wary and did not meet with him.