Updated at 1:48 p.m. ETAttorney General Jeff Sessions is trying to defend President Trump in the Russia imbroglio, but Trump has slapped Sessions down — again — for work he says isn't good enough. The attorney general said on Tuesday Justice Department Inspector General Michael Horowitz would look into the kernel of what Republicans call the real Russia story: the alleged abuse by the FBI and Justice Department of their surveillance powers. Horowitz operates independently within the department. His office has acknowledged receiving a request to look into the FISA matter.Trump said on Wednesday morning that won't cut it.Sessions responded later in the day on Wednesday defending himself and the Justice Department."We have initiated the appropriate process that will ensure complaints against this department will be fully and fairly acted upon if necessary," Sessions said. "As long as I am the attorney general, I will continue to discharge my duties with integrity and honor, and this department will continue to do its work in a fair and impartial manner according to the law and Constitution."There's a lot going on between these two leaders. Here's a look at the backstory.Fact check: Does Horowitz have "prosecutorial power?" Trump is correct that the IG probably would not bring charges himself and make a case on his own if he opened an investigation and then discovered wrongdoing. The inspector general refers his findings to the FBI or others within the Justice Department for action — as with a case from earlier this month, for example, in which the IG's office looked into alleged misconduct by a senior FBI agent. Fact check: Is Horowitz "already late with reports on Comey etc?" The IG's office has been looking into the FBI's handling of its investigation into Hillary Clinton's private email server. That story and the conduct of officials including former FBI Director James Comey — whom Trump fired — has been a main focus for Trump and his allies. Not only do they argue the FBI and Justice abused their surveillance powers, they also argue Clinton should have faced criminal charges. Deputy Attorney General Rod Rosenstein told Congress that he expected the IG report about that era to be complete soon, although it is not yet public. There have been indications that early drafts have circulated internally with some consequences already: Former Deputy FBI Director Andrew McCabe, who had been expected to retire this year, may have done so becausebureau officials were anxious about how the Horowitz report treated his role in the Clinton email matter or other cases. Fact check: "Isn't the I.G. an Obama guy? Why not use Justice Department lawyers?" Yes. Horowitz was confirmed by the Senate in 2012. He is a Justice Department lawyer, though. The background: What Trump apparently wants is for Sessions to launch a full-scale criminal investigation into the applications the FBI and Justice Department made in 2016 to conduct surveillance on his onetime campaign adviser, Carter Page. As Sessions responded, he says he is proceeding by the book.Republicans have zeroed in on that warrant and argued it was obtained improperly: The FBI and Justice Department excluded the fact that part of the evidence in their application, the infamous Russia dossier, was anti-Trump political agitprop, Republicans say. In effect, a "biased" FBI hoodwinked a judge on the Foreign Intelligence Surveillance Court, as the argument goes, and violated Page's civil rights. That argument was the thesis of the secret memo released early in February by the House intelligence committee's Republican majority. On Saturday, Democrats released their response. It argued that the FBI and DOJ had acted appropriately. Not only that, the surveillance on Page yielded what the Democrats' memo called "valuable" foreign intelligence — suggesting he was, in fact, contacting foreign spies or engaged in other clandestine activity.Trump's tweet on Wednesday underscores the difficulty of sustaining a strong political defense on such wonky, disputed grounds. The basis for Republicans' objection is complex. What's more, the argument that the Justice Department and FBI abused their powers out of anti-Trump animus is undercut by the disclosure in the House intelligence committee memos that both Obama and Trump administration officials signed warrant applications for Page. Even Rosenstein, Trump's own appointee, thought there was sufficient cause to ask for surveillance to continue. The president supported releasing House Republicans' memo over the objections of his own administration, fast-tracked it into the open in just one week and made possible for it to appear unexpurgated. Democrats' countermemo took much longer and appeared full of redactions by the FBI and Justice Department. Trump's tweet on Wednesday, however, suggests his patience with this thread of his defense might be running out. He has blasted the attorney general before and other supporters also criticized Sessions' initial unwillingness to appoint a second special counsel to begin investigating the Justice Department's current special counsel, Robert Mueller.So Sessions' strategy of simply raising more questions about the proper use of FISA may no longer cut the mustard — so much so that Trump asked why he should even bother. That's why the attorney general's efforts, for Trump at least, are "DISGRACEFUL!"NPR correspondents Carrie Johnson and Ryan Lucas contributed to this report. Copyright 2018 NPR. To see more, visit https://www.npr.org/.