Is it significant that Jeff Sessions, the current Attorney General, had recused himself from testifying? What does that mean exactly?
The Attorney General recused himself from the investigation into alleged collusion between the Trump campaign and Russia because he met with the Russian ambassador to the United States during the campaign while Sessions was a prominent Trump surrogate (and then declined to share those details when asked about them during his Senate confirmation hearing). There’s a clear conflict there because Sessions, as Attorney General and the nation’s chief law enforcement officer, is the Justice Department official ultimately responsible for the overall investigation and could very well be one of the subjects of the investigation.
By recusing himself from the investigation, Attorney General Sessions basically is removing himself from any potential decision-making process regarding the investigation. That’s why the Deputy AG was responsible for appointing the Special Prosecutor and has been in a more public role than Deputy Attorneys General traditionally are.