The warrant was issued and then renewed three separate times. Each time, as is standard in seeking a FISA warrant, a judge reviewed extensive information before issuing it. The fact that the warrant was renewed three times indicates that the F.B.I. obtained useful intelligence each time — a judge wouldn’t have approved a renewal if the prior warrant came up empty. That suggests that once the warrants were issued, they revealed important evidence.

In addition, the timeline set forth in the memo indicates that the FISA warrants were submitted by both the Obama and Trump administrations. The initial surveillance began before Mr. Rosenstein was deputy attorney general, and by the time he was at the Justice Department, he approved renewal applications that were based on the intelligence gathered from the earlier surveillance — not the dossier.

On the issue of bias, whenever the Justice Department seeks a warrant, they must present extensive evidence to a judge, who decides whether to issue the warrant based on that evidence. After the fact, defendants can challenge warrants by arguing that the government recklessly excluded information that would have caused the judge not to sign the warrant.

Courts have repeatedly held that even when the government omitted the criminal history of the informant or the fact that the informant was paid, it didn’t matter unless the omitted information would have caused the judge not to sign the warrant.

The Nunes memo claims to show that the warrant was obtained unlawfully, but there is no way of knowing that without examining the extensive evidence submitted in conjunction with the warrant, which the memo does not do. Given that Mr. Steele was a former intelligence officer, not a flipper with an extensive criminal history, it will be hard to show that a judge would have believed he was lying if the source of his funding was included in the application.

Given how little substance there is to the Nunes memo, the Republicans made a misstep by pushing through its release in a partisan manner. The specter of an unreleased memo was more menacing than the thin allegations revealed in the memo itself, which are hotly disputed by congressional Democrats.

Although at least one Republican maintains that the memo shows that Mr. Rosenstein, Mr. Comey and others committed “treason,” the memo itself does not allege that the F.B.I. or Department of Justice knowingly used false information or even that the information they used was false. Because the allegations in the memo are legally irrelevant, I would be surprised if the memo was more than a short-lived publicity stunt.

This is not the result Mr. Nunes expected when his staff wrote the memo, but that could be its lasting impact.