The infamous 35-page “Steele dossier” that, among other things, claims the Russians have a kinky sex tape of then-businessman Donald Trump, roared back into the news this week with the revelation that the Hillary Clinton campaign and the Democratic Party paid for at least part of the research.

Trump and his allies used the news to argue that the dossier’s most serious allegations — including collusion with the Russian government during last year’s presidential election — are partisan slander and should not be taken seriously. Trump deemed the payments for the research dossier “the real collusion” in an interview with Fox Business’ Lou Dobbs this week.

“Everything the Clinton campaign and the DNC falsely accused this campaign of doing over the last year they were doing themselves,” White House spokeswoman Sarah Huckabee Sanders added in a Fox News interview.

Democrats rolled their eyes at the breathless outrage and suggested conservatives were faking it in an effort to discredit the ongoing federal investigation into Russia’s meddling in the presidential election and whether Trump & Co. were involved. Opposition research is usually funded by the opposition, after all.

The most damning details of the dossier have not been independently confirmed, but special counsel Robert Mueller and congressional committees have been looking into it.

Here’s a rundown of what was revealed this week and what it could mean (or not mean) for the Russia investigation:

Hillary Clinton’s campaign helped pay for the “Steele dossier” produced by Fusion GPS

The law firm Perkins Coie retained Fusion GPS in April of 2016 to look into Donald Trump on behalf of the Hillary Clinton campaign and the Democratic National Committee, according to the Washington Post. The research firm had already been investigating Trump on behalf of a still-unknown Republican donor trying to stop Trump during the 2016 Republican primary.

Fusion GPS then hired former British intelligence officer Christopher Steele, who compiled the reports and began feeding them to U.S. media outlets in the fall of 2016. Representatives close to Clinton claim she never saw the dossier during the campaign and wishes the information had gotten out before November. Former Clinton press secretary Brian Fallon agreed with that sentiment, tweeting: “If I’d gotten his dossier before Nov. 8, I may have tried to convince Mook & Podesta to let me hold a Comey-style press conference to read it.”

Opposition research is normal

Opposition research is normal, and it is not unusual for campaigns to hire outside firms to look for salacious and scandalous details about their opposition. In fact, most campaigns, especially presidential campaigns, consider it a necessity now — even the Trump campaign admitted as much in explaining why they met with Kremlin-linked operators who promised dirt on Hillary Clinton.

It is, however, unusual for that research to involve skulking around all over Russia and other “Tinker Tailor Soldier Spy” kind of behavior. But Trump, with his complex web of international business ties, was also not a normal candidate.

Did Clinton’s campaign do anything wrong? Maybe.

Hiring Fusion GPS is not a crime. It’s possible the Clinton campaign violated Federal Elections Commission (FEC) law because it was able to avoid disclosing that it had retained Fusion GPS by going through the Perkins Coie. The watchdog group Campaign Legal Center argued as much in a complaint to the FEC Wednesday.

Graham M. Wilson, a partner at the law firm, disputed the group’s interpretation of the law as “patently baseless,” and told the New York Times the firm complied with FEC regulations since research was done “to support the provision of legal services, and payments made by vendors to sub-vendors are not required to be disclosed in circumstances like this.”

But it’s what happened after the election that could get top Democrats in trouble. Clinton campaign chairman John Podesta and former DNC chair Debbie Wasserman Schultz told Congress this past year that they did not know who paid Fusion GPS, according to a CNN report Thursday. If they lied to Congress and did know that the Hillary campaign and the DNC were paying Fusion GPS, then that is a federal crime.