The great debate about whether the FBI spied on the Trump campaign continues. The question is why there is still any argument. The newly released report from Justice Department Inspector General Michael Horowitz shows that by any definition the FBI did indeed spy.

The proof is in the details of the report. In addition to the much-discussed wiretap of Trump campaign foreign policy adviser Carter Page, Horowitz discussed the bureau's use of what is called a CHS (a confidential human source, or, in more common terms, an informant) and a UCE (an undercover employee, or a secret agent) to gather information from at least three targets in the Trump campaign. One was Page, another was George Papadopoulos, also a member of the advisory team, and the third was an unnamed "high-level Trump campaign official who was not a subject of the Crossfire Hurricane investigation."

Horowitz described "multiple CHS operations undertaken by the Crossfire Hurricane team." There were "numerous CHS interactions with Page and Papadopoulos." There was the CHS contact with the high-level campaign official. And then there were "additional CHSs" who attempted to contact Papadopoulos but did not succeed.

All the meetings and conversations were secretly recorded by the FBI. Some were also monitored live, as they happened, by agents and supervisors. The Horowitz report quoted liberally from transcripts of the recordings.

The Trump campaign was "clearly spied upon," Attorney General William Barr said in an interview with NBC Tuesday. "I mean, that's what electronic surveillance is. I think wiring people up to go in and talk to people and make recordings of their conversations is spying."

That is correct. But remember what Barr said back in April after he launched another investigation, this one by U.S. Attorney John Durham, of the Trump-Russia probe: "The question is whether it was adequately predicated." Did the surveillance have a proper basis?

Of course, even if it was adequately predicated, it was still spying. That's why the Foreign Intelligence Surveillance Act court, known as the FISA court, which approves wiretaps and other surveillance, is colloquially known as the "spy court."

Beyond that, Horowitz offered a mixed bag on the question of predication.

Yes, the FBI met its own low standards for sending an informant to secretly record a target. The Horowitz report included a touch of wonder, and worry, that FBI rules allow fairly low-level officials to order the use of a CHS who can secretly record a target. "We found it concerning that [Justice Department] and FBI policy did not require the FBI to consult with any Department official in advance of conducting CHS operations involving advisers to a major party's presidential campaign," Horowitz wrote.

So the spying "received the necessary FBI approvals," Horowitz said. But at the same time, the report suggested the necessary approvals were far less than what was needed under the circumstances.

And that was just the in-person spies. The Page wiretap was a disaster that could have long-lasting repercussions for the FBI. Yes, the bureau went to the FISA court and received its approval to spy on Page. But a "central and essential" element of the wiretap application was the Steele dossier, which the report made clear had zero credibility. In addition, the FBI had received information — ironically, from its sketchy CHS snooping — that "was inconsistent with, or undercut, the assertions contained in the FISA applications" that the FBI used to argue that probable cause existed to wiretap Page. That meant in some cases "inaccurate information" was included in the wiretap applications.

"Inaccurate" is a nice way to put it. Another word for the information from the Steele dossier that the FBI passed on to the court is "misleading." And the report made it clear that the FBI knew the material was faulty.

"That was misleading to the court," Horowitz told the Senate Wednesday.

And there was still more. It turns out the FBI used what should have been a routine intelligence briefing of the Trump campaign to pursue its investigation. It happened in August 2016, when the Office of the Director of National Intelligence briefed both the Trump and Hillary Clinton campaigns. For the Trump group — a session that included the candidate himself and also FBI target Michael Flynn, a top national security aide — an FBI supervisor from the Crossfire Hurricane team attended to see if Trump's or Flynn's behavior might reveal some evidence in the case. "No one at the [Justice Department] or ODNI was informed that the FBI was using the ODNI briefing of a presidential candidate for investigative purposes," Horowitz wrote. After the briefing, the agent wrote up a report on what he heard.

At Horowitz's appearance Wednesday, Senate Judiciary Committee Chairman Lindsey Graham asked, "Was that FBI agent spying on Donald Trump?"

"It was a pretext meeting," Horowitz answered. "The agent was actually doing the briefing, but also using it for the purpose of investigation."

In short, the FBI, acting under false pretenses, spied on Trump and Flynn in plain sight.

The Horowitz report noted the potentially corrosive effect of what the FBI did. "We concluded that the FBI's use of this briefing for investigative reasons could potentially interfere with the expectation of trust and good faith among participants in strategic intelligence briefings, thereby frustrating their purpose," the report said.

Put it all together, and there was a lot of spying on the Trump campaign — by confidential informants, in a wiretap, even in a supposed intelligence briefing. Yet defenders of the Trump-Russia probe still maintain that no spying took place and that the FBI followed proper procedures. After Horowitz, that's a difficult case to make. The fact is, the FBI not only spied on the Trump campaign, it did it in the worst way.