Senate Republicans are suddenly ramping up their efforts to dig into the origins of the probe of President Trump’s 2016 campaign. Two committees are launching investigations that essentially ask whether there was an effort at the highest levels of the Obama administration or the FBI to undermine Trump.

This week, the Senate Judiciary Committee took a step toward this by issuing a list of dozens of names of Obama officials they would like to subpoena, either for documents or testimony. And Tuesday, the Senate’s homeland security committee issued a subpoena related to an investigation of Hunter Biden.

Why are they doing this now? The committees say that if there was wrongdoing by the intelligence community as Trump got his presidency started, the American public deserves to know about it.

“You’re not crazy or a conspiracy theorist if you see a pattern of institutional unfairness toward this president,” Senate Majority Leader Mitch McConnell (R-Ky.) said Tuesday. “You would have to be blind not to see one.”

Politically, the timing is ripe for Republicans. The election is less than six months away. Trump is getting negative marks from the public for his coronavirus response, and Senate Republicans are worried about hanging on to their six-seat majority.

The Trump campaign has started its own campaign to try to discredit Democrats’ presumptive nominee, former vice president Joe Biden. Trump is trying to loop Biden into his long-standing grievances against the intelligence community for investigating him in the first place. That seems to be a factor in the nebulous, baseless “Obamagate” he’s started tweeting about.

Senate Republicans are all in. “I just think that everybody realizes that our fortunes sort of rise or fall together,” Sen. John Thune (S.D.), a leader of the Senate GOP caucus, told Politico on Tuesday.

That means some names that you may have filed away could be resurfacing in the next few weeks. Here’s a refresher on them and how they might come up.

James B. Comey: He was the FBI director during the 2016 election. Under his supervision, the FBI had separate investigations open into Trump campaign advisers and Hillary Clinton. His firing by Trump led the Justice Department to appoint special counsel Robert S. Mueller III, who investigated Trump-Russia connections for almost two years. Comey has since become a vocal Trump critic. Trump allies have alleged that Comey’s controversial leadership of the FBI underscores how agents may have politicized their investigations against Trump.

In particular, Sen. Ron Johnson (R-Wis.), chair of the Senate’s homeland security committee, has alleged that Comey encouraged FBI agents to keep open their investigation of Trump’s incoming national security adviser, Michael Flynn.

“I’ve always felt that there has been a concerted effort to sabotage this administration, and it began the day after the election when, according to these folks, the wrong person won,” Johnson said on Fox News recently.

But what Johnson doesn’t say is that the FBI’s investigation into Flynn may have been justified. A former top Justice Department official wrote recently in the New York Times that while they weren’t sure there needed to be a continuing investigation of Flynn, “we certainly agreed that there was a counterintelligence threat” regarding Flynn and his conversations with the Russian ambassador to the United States. Flynn would eventually plead guilty to lying to the FBI about those conversations. Yet now he wants to withdraw that plea, and the Justice Department under Attorney General William P. Barr wants to drop the prosecution. A federal judge has the final say.

Senate Judiciary Chairman Lindsey O. Graham (R-S.C.) is focused on how FBI officials, under Comey, got a secret court to sign off on a warrant to conduct surveillance on former Trump adviser Carter Page. A subsequent government report found errors in their application to surveil Page. Another report found that errors turned out to be quite common in FBI wiretap requests (known as Foreign Intelligence Surveillance Act applications) for numerous investigations. That suggests more widespread systemic failures in how the FBI applies for wiretap warrants, rather than any political motivation targeted at Trump, writes The Post’s Ellen Nakashima.

Republicans have seized on these errors as evidence that the intelligence community had it out for Trump.

Andrew McCabe: He took over the FBI after Comey was fired and authorized the FBI’s investigation into whether Trump personally obstructed justice by trying to stop the special counsel probe. He was later fired roughly a day before he would have qualified to receive his full retirement income. Trump has tried to use the fact that McCabe’s wife ran for office in Virginia and got donations from high-level Democrats to paint the entire FBI as politically motivated against him. (An inspector general report found no evidence of that.) More recently, Trump was furious to find McCabe was not charged with a crime in connection with allegations that he lied about sharing information with the media when he was in FBI leadership.

Blue Star Strategies: On Wednesday, Johnson’s committee — over the objections of Democrats — approved a subpoena for documents from this lobbying firm. Johnson has asked whether it used Hunter Biden’s name as leverage when it was trying to lobby the Obama State Department for better treatment of the Ukrainian company for which Biden was a board member. Blue Star has said no subpoena is necessary, reports The Post’s Mike DeBonis: “At no time have we ever stated or indicated in any way that we would not cooperate. Therefore, we are puzzled, despite our willingness to cooperate, why the Committee is proceeding to vote on a subpoena.”

James R. Clapper Jr.: He was the director of national intelligence under President Barack Obama. His name appears on a list that GOP senators released last week of officials who requested to see the name U.S. persons showing up in redacted intelligence reports from the National Security Agency from late November through mid-January.

Republican senators have alleged that Obama-era officials asked which American showed up in intelligence reports as talking to Russia’s ambassador in late 2016 about Obama’s sanctions for election interference. (That person was Flynn, who later lied about those conversations.) It’s called unmasking, a legal and common practice in the intelligence community that is also available to top administration officials. The question GOP senators are asking seems to be: Did the Obama administration — including Joe Biden — somehow play a role in getting the FBI to investigate one of Trump’s allies? There’s no evidence of that, and unmasking by definition means you don’t know the name you’re requesting be unmasked.

But as The Post’s Ellen Nakashima reports, the unmasking list the NSA provided could not have been related to the Flynn call with the Russian ambassador, because it was the FBI -- not the NSA-- that wiretapped that call and wrote up a summary on it. And in that summary, Nakashima reported, the FBI did not redact Flynn’s name, so there was never any need to make an unmasking request related to his call with the Russian ambassador.

John Brennan: He is the former CIA director under Obama. His name, too, appears on the NSA unmasking request list for various intelligence reports. He was also an attendee at an Oval Office meeting on the day of Trump’s inauguration with Obama, Biden, Comey and other top officials about Russian interference in the 2016 election, where they talked about Flynn.

Susan E. Rice: We know about this meeting because of Rice, who is also on Graham’s list to subpoena. Rice was the outgoing national security adviser, and she wrote in an email to herself detailing that 2017 meeting. On Tuesday, the Trump administration declassified it. In it, Rice says Comey expressed concern that Flynn was having so many conversations with the Russian ambassador. Rice says Obama urged Comey and the FBI to do all investigations of Trump officials “by the book,” and Comey emphasized that he was.

Republicans have seized on this email as suggestive that perhaps the FBI wasn’t investigating by the book, or yet more evidence that Obama and Biden were directing a spying campaign on the incoming Trump administration. But in the email, Rice writes at the time: “The president stressed that he is not asking about, initiating or instructing anything from a law enforcement perspective.” Biden said he wasn’t aware of any criminal investigation into Flynn.

Denis McDonough: He was Obama’s chief of staff. His name also appears on the list of top Obama administration officials who may have asked to unmask Americans in intelligence reports.

Peter Strzok: He was an FBI agent who played a role in election-year investigations into Trump and Clinton and was on the special counsel investigation. But he lost that job after text messages were revealed of him talking negatively about Trump with another FBI official, Lisa Page, with whom he was having an affair and who is also on Graham’s subpoena list.

Trump and his congressional allies have elevated Strzok and Page as examples of how deep the alleged animus within the FBI against him goes, as part of an effort to discredit the Mueller probe. But the watchdog in the Justice Department found that their personal political views did not actually affect the investigations they worked on.

Correction: This post has been corrected to clarify that James Clapper’s name did not appear on a list specifically requesting to unmask Flynn from an FBI report.