Now that the Foreign Intelligence Surveillance Act (FISA) application for an order to surveil former Trump campaign advisor Carter Page has been released in heavily redacted form, the attacks on the FBI’s application have been predictably loud yet incorrect. They miss the critical question related to such an application: was there probable cause to believe that Page was an agent of a foreign power?

Even putting aside the large portions of redacted material (which likely further support the application but are redacted because of the highly sensitive nature of the information), the unredacted portions easily meet this probable cause standard and support the FISA court’s multiple orders.

One source upon which many of these critiques rely (including those of President Donald Trump) is Andrew C. McCarthy, who, like the three authors, is a former federal prosecutor. On Fox News and in the National Review, McCarthy makes three primary arguments: (1) the so-called Steele dossier was “the driving force behind the Trump-Russia investigation”; (2) the FISA court was not told that the Clinton campaign was behind Steele’s work; and (3) the FBI did not “verify” the factual allegations contained in the dossier.

McCarthy’s first two points should be quickly dismissed. The first Page FISA application, however, was not obtained until October 2016, well after the Trump-Russia investigation began and even after Page himself had left the campaign. McCarthy (and Trump) attempt to pinpoint the Page FISA application as the central reason for the initiation of the Trump-Russia investigation in a sleight-of-hand attempt to discredit the investigation, but the facts just don’t support that assertion.

The facts also do not support McCarthy’s second point (one that Congressman Devin Nunes misleadingly emphasized in his infamous memo about the warrant): that the FISA court was not informed about the Clinton campaign’s financial support for Christopher Steele’s work. In fact, the original application included more than a one-page footnote extensively informing the court about the fact that Steele was hired essentially to dig up dirt on Donald Trump, which more than adequately informs a court of his potential bias. Whether the Clinton campaign was the source of the payments – which Steele has testified before Congress that he did not know, because he was retained by Fusion GPS – is irrelevant to the substance of the disclosure of potential bias. Nothing more is required or necessary in a warrant application than revealing the fact of a source’s potential for bias.

The third point, and the crux of McCarthy’s argument, is that the FBI did not properly “verify” the information in the application, which is a technical requirement in a FISA application. McCarthy claims that the FBI was not permitted to rely solely on hearsay information provided by Steele, its source of information, but rather was required to test the credibility of, and reliance on, each sub-source who gave information to Steele. But that is simply not what is required in FISA applications (or criminal wiretap applications), and in particular under the Woods Procedures that govern FISA applications. Under FISA, “verification” simply requires both the FBI and lawyers in the Department of Justice to verify that the facts as set forth in the affidavit are supported by evidence obtained as part of the investigation. That does not mean, however, that the FBI is required, for example, to travel to Russia to interview a sub-source to confirm that the sub-source actually did tell Steele what Steele reported to the FBI. That, of course, almost certainly would not be possible. It is therefore not surprising that McCarthy cites no authority for his assertion that such a step is required.

The reason why hearsay information is permitted in warrant applications is simple: it is hard enough for law enforcement to develop sources who can infiltrate criminal organizations or foreign threats to our national security. If the FBI were required to not only learn of the information from its own sources but also confirm that information with the sub-sources, it would not be able to do its job. Instead, the FBI is legally entitled to rely upon the assertions of a previously credible source, such as Steele, in relaying information from other sub-sources to whom the FBI does not have direct access.

Our nation’s law permits this process because the standard for a warrant such as this one is probable cause, not the higher standard of beyond a reasonable doubt that applies in a criminal trial. McCarthy characterizes the FISA application to include “ serious, traitorous allegations against an American citizen and, derivatively, an American presidential campaign.” That is wrong. The FISA application made no such allegations nor did it charge Page with a crime or violation of law. Rather, in order to further investigate credible allegations of wrongdoing, the FISA application simply provided evidence that there was probable cause to believe that Carter Page was an agent of a foreign power and may have, or may be about to, commit violations of criminal law.

Probable cause means a “fair probability.” It is more than a “mere suspicion” but far less than the “reasonable doubt” standard required to convict someone of a crime. While information from a source such as Steele’s more than meets this probable cause standard, that is clearly not all that the warrant relied upon. Just from what we can see in unredacted form – and the majority of the application is redacted – it also walks through Page’s interactions several years ago with Russians who were eventually charged with being agents of Russian intelligence. McCarthy somehow claims that he knows that the redacted sections do not corroborate or add to Steele’s information. But he misses the point. Even if the specific details in the Steele dossier are not directly confirmed, the fact that other evidence unrelated to the dossier corroborates the dossier’s main allegations is sufficient to support a finding of probable cause.

Even from the limited unredacted information available to the public, including the criminal charges brought against the Russian individuals who associated with Page, the repeated and expanded applications for renewals, and the fact that the Republican Party platform on Russia and Ukraine changed during the operative time period of Page’s involvement in the campaign, it is our view that the FISA application sufficiently makes out the necessary showing of probable cause to support the court’s approval. Four separate federal judges agreed.

In his National Review article McCarthy says that the FBI, “which I can’t help but think of as my FBI after 20 years of working closely with the bureau as a federal prosecutor, would never take an unverified screed and present it to a court as evidence.” Similarly, we cannot imagine the FBI that we know after decades of combined experience would ignore the evidence that was presented to them and decline to seek a warrant for Carter Page when it did. In fact, if the FBI had failed to investigate such allegations, we (and the American people) would’ve been entitled to find them derelict in carrying out their duties.

Daniel S. Goldman, currently a Fellow at the Brennan Center for Justice, served as an Assistant U.S. Attorney for the Southern District of New York from 2007 to 2017. Miriam Rocah, currently a Distinguished Criminal Justice Fellow at Pace University Law School, served as an Assistant U.S. Attorney for the Southern District of New York from 2001 to 2017. Barbara McQuade, currently professor from practice at the University of Michigan Law School, was the U.S. Attorney for the Eastern District of Michigan from 2010 to 2017.