Attorney General Bill Barr said he has “questions” and “concerns” about the FBI’s handling of the Russia investigation Wednesday, and that he will review “both the genesis and the conduct of intelligence activities directed at the Trump campaign during 2016.”

The comments — made by Barr during Senate testimony Wednesday morning — make clear that President Trump now has an ally at the top of the Justice Department, who may be sympathetic to some long-running conservative criticisms about the Russia probe’s handling.

“I think spying on a political campaign is a big deal,” Barr said, using language the president and his allies have often employed in their criticisms of the Russia probe. His review, he said, will be aimed at assessing whether that spying was “adequately predicated.”

Barr added that he has “no specific evidence” of misconduct right now, but that he needs to “explore” that question, to make sure intelligence agencies stayed in “their proper lane.”

Before this, department leaders like Deputy Attorney General Rod Rosenstein and FBI Director Chris Wray have tended to publicly defend the integrity of the investigation, voicing full-throated support for the probe and denying that it was a “witch hunt.”

But Barr conspicuously declined to do any such thing. Asked specifically whether the investigation was a witch hunt, he said, “it depends on where you sit,” and that people who were “falsely accused” could well hold that view.

He also said that to the extent there were “issues at the FBI,” it was “probably a failure among a group of leaders there at the upper echelon” — implying his concerns are about former officials who have been the target of much criticism from the right, such as James Comey, Andrew McCabe, and Peter Strzok.

What Barr’s “spying” comments — and his review — may mean

Barr did not specify what specifically he had “concerns” about, and what exactly he was referring to when he mentioned “spying” on the Trump campaign. He could be referencing information that is not yet public.

But there are three interconnected criticisms conservatives have long made about things the government did during the 2016 presidential election related to the Russia probe:

1) The Steele dossier: In April 2016, a top Democratic campaign lawyer working on behalf of Hillary Clinton’s presidential campaign and the DNC retained an opposition research firm, Fusion GPS. Fusion then subcontracted with Christopher Steele, a retired British spy, to look into Donald Trump’s ties to Russia.

Steele put together a series of alarming-sounding reports asserting, among other things, that there was a “well-developed conspiracy of cooperation” between Trump and Russia, that Trump was vulnerable to Russian blackmail on sexual matters, that Trump’s team was working closely with the Russian government on the hacking and leaking of Democratic emails, and that Trump advisers would be paid off from the privatization of a Russian oil company. Steele soon gave his reports to the FBI, and the bureau started looking into them.

The problem is that, well, none of that may be true. Certainly none of it was backed up by charges filed in the Mueller probe. So conservatives have been arguing that the FBI inappropriately relied on a phony document tied to the Clinton campaign as a basis to investigate the Trump campaign.

Russia probe defenders responded by pointing out that, actually, the investigation was opened not because of the dossier, but because of a tip that George Papadopoulos was saying he knew the Russians had Hillary Clinton’s emails. They’ve also argued that the dossier’s allegations merited investigation even if they did turn out to be false.

2) The informant: During the summer of 2016, the FBI asked a confidential informant — now known to be a retired university professor based in Britain named Stefan Halper — to reach out to Papadopoulos, to try and find out what he knew about those hacked emails and Trump campaign-Russia connections. Halper had also reached out to Carter Page beforehand, but it’s not clear if that was at the FBI’s behest.

When this came to light last year, President Trump and his allies dubbed this “Spygate.” They argued that the FBI should not have been deploying a confidential informant against a presidential campaign, claiming this amounted to “spying.”

But others argued that the FBI was merely investigating something it had a very good reason to investigate — whether Papadopoulos had inside information about the Russian government’s possessions of hacked emails. My colleague Zack Beauchamp wrote last year that the evidence currently suggests that rather than being an attempted political attack on Trump, Halper’s activity was part of “a legitimate counterintelligence operation.”

3) The Carter Page FISA warrant: Finally, the centerpiece of the conservative case that the Russia investigation went too far has long been that, in October 2016, the government got a FISA warrant to surveil Carter Page.

The background to this is that Page had made a trip to Russia that summer. After his trip, the Steele dossier’s allegations that Page was part of a Russian conspiracy involving hacked emails and financial payoffs made it both to the FBI and into public media reports.

This led the Trump campaign to disassociate themselves from Page in September 2016, and the next month — once Page was a former adviser — the Justice Department applied to the Foreign Intelligence Surveillance Court for a warrant to surveil Page’s communications.

There’s already been a great deal of controversy about that FISA application (which has been released, though in heavily redacted form). It’s clear that the government did rely on Steele dossier information in that application — but that they had other sources of information as well.

What’s not entirely clear is how strong that other evidence against Page in fact was (though we should note again that the application was approved and reviewed by a judge). Page was not, in the end, charged with any crimes as part of the Russia investigation, and he has steadfastly maintained his innocence of wrongdoing and claimed his civil liberties were violated by this surveillance.

In any case, the Justice Department’s inspector general, Michael Horowitz, has already been reviewing the Page FISA application for some time, and Barr said this week that Horowitz will probably finish that review by May or June.

As for Barr’s plans for a review, they don’t yet seem entirely firm — he said he wanted to “pull together all the information from the various investigations that have gone on” to look at the full picture about what happened (that is, it would be broader than the inspector general review). But his comments make it clear enough that he’s taking long-running concerns from President Trump and his allies seriously.

For more on the investigations into the president, follow Andrew Prokop on Twitter and check out Vox’s guide to the Trump-Russia investigation.