Deputy Attorney General Rod Rosenstein. (Evan Vucci/AP)

John S. Martin served as U.S. district judge for the Southern District of New York from 1990 to 2003 and as U.S. attorney for that district from 1980 to 1983.

Deputy Attorney General Rod J. Rosenstein has become the latest bogeyman for members of the House Freedom Caucus. As these Republicans see it, Rosenstein is guilty of impropriety in connection with the Justice Department’s application to surveil former Trump campaign adviser Carter Page based on the untenable assertion that the FBI and Justice Department deliberately misled the Foreign Intelligence Surveillance Act Court.

The assertion is false, not least of all since Rosenstein was not involved in the original FISA application (he only became involved when signing the third extension of the application). But that hasn’t prevented members of the Freedom Caucus from calling for Rosenstein’s impeachment this week — a motion that has since been tabled, reportedly because House leadership agreed to hold a vote on whether Rosenstein is in contempt of Congress later in September.

Regardless, the claim that Rosenstein or anyone else involved in the FISA application did something inappropriate is wrong. Having served for 13 years as a federal judge, I can say with confidence that any judge who reviewed the FISA applications would have granted them and that there is no basis to assert that anyone attempted to mislead the court.

Applications for warrants for either electronic surveillance or a physical search usually rely on information provided by informants who have some motive other than a concern for the general good. In a typical case, the informant is a criminal who is hoping for either a monetary reward or some help with a pending criminal case. What is important to the judge is not whether the informant has a motive, but whether there is reason to believe that the information is reliable. Usually, the judge accepts the informant information as reliable because the affiant swears that the informant has provided reliable information in the past.

This is exactly what happened in the Carter Page application. The first time the affidavit mentions information from “Source #1” — understood to be Christopher Steele, the former British intelligence officer who authored the infamous Trump dossier — there is a footnote stating that he had been a source in the past. The affidavit goes on to state: “Source #1’s reporting has been corroborated and used in criminal proceedings and the FBI assesses Source #1 to be reliable.”

The court was also advised by the FBI that the source had been compensated. The affidavit states that Source #1 had an intelligence gathering business and that he had been hired by a “U.S. person to conduct research regarding Candidate #1’s ties to Russia.” The affidavit also states: “The FBI speculates that the unidentified U.S. person was likely looking for information that could be used to discredit Candidate #1’s campaign.” Although the affidavit does not identify Trump by name as Candidate #1, the totality of the information in the affidavit makes that clear.

It is inconceivable that any of the judges who signed the Page warrants would not have signed them if they had known that it was someone associated with the Clinton campaign, which had hired Steele. Whatever Steele’s motivation, the most important fact was that he had provided information in the past that was reliable and had been used in criminal prosecutions. Moreover, the disclosure that was made gave the judge sufficient information to understand the possible political motivation behind the research. Federal judges do not live in a vacuum.

The only application Rosenstein signed contained the additional information that Steele had been terminated as an informant by the FBI because he had given information to the media and that Page sent a letter to the Justice Department complaining that the Clinton campaign had falsely accused him of meeting with two of the Russian agents referred to in the warrant application. There is absolutely no basis for a claim that Rosenstein somehow was part of a conspiracy to keep from the FISA court the fact that the Clinton campaign was probably responsible for hiring Source #1.

The actions of the Freedom Caucus members are not only baseless, they are also shameful. While they call for the appointment of a special prosecutor to investigate Rosenstein, it may be more appropriate to appoint a special prosecutor to investigate an attempt to corruptly obstruct justice by members of Congress who so obviously use their office to intimidate the deputy attorney general and to undermine the credibility of special counsel Robert S. Mueller III’s investigation.