Trump stopped short of naming the "bad and the conflicted". But his line of attack was in keeping with charges by Trump surrogates Newt Gingrich - who claims Mueller is "hiring only Democrats … bad people" - and Kellyanne Conway, who criticised Mueller's legal team for past political donations to the Democratic Party. US President Donald Trump on Thursday. Credit:Bloomberg This line of attack acknowledges the odd realities of Trump's Russia crisis, which is now swarming with lawyers and Mueller's burgeoning team of criminal investigators. As revealed in a series of public hearings by the Senate Intelligence Committee, key administration witnesses are refusing to disclose the detail of their conversations with Trump, which could be pivotal in making a case against him and his associates. But their claimed right to protect these conversations, and Attorney-General Jeff Sessions' effort this week to reserve Trump's right to invoke executive privilege, hold no water in the criminal investigative process. That's because back in the Watergate investigation, the Supreme Court ruled administration officials could not withhold evidence by claiming executive privilege.

But this business is unlikely to be resolved, at least as it concerns Trump, in the criminal justice system - because the Justice Department has long held that a sitting president cannot be indicted. Refused to answer some questions: US Attorney-General Jeff Sessions. Credit:Bloomberg Consequently, the findings of the Mueller investigation will end up back in Congress, where the Republican Party-controlled House will have to make an initial decision to impeach Trump. The criminal investigation is an essential element of the investigation, but "this Russia thing" will be resolved politically – hence the decision by the White House to fight along political lines. That meant that when The Washington Post dropped its bombshell report on Wednesday evening – that Trump, personally, was under investigation for obstruction of justice – his legal team didn't even bother to refute the charge. Instead, a spokesman vented about yet another leak from within the investigation. Former FBI Director James Comey smiles during a Senate Intelligence Committee hearing last week. Credit:AP

Trump had claimed that then FBI director James Comey had informed him three times, and Comey confirmed in Senate testimony last week, that Trump had not been under personal investigation. But that seems to have changed with Trump's decision to sack Comey. Remarkably, Trump is reportedly considering a move to sack Mueller. When Trump associate Chris Ruddy revealed as much this week, there was massive pushback – inside and outside the administration. US President Donald Trump, accompanied by first lady Melania Trump, signs the Supreme Court guest book, on Thursday. Credit:AP Trump is reportedly antsy that Mueller's investigation could be "compromised" – an argument already being finessed by Trump loyalists who say that Mueller has a conflict of interest because his former law firm represented Ivanka Trump and Jared Kushner, even though the Justice Department has knocked down that line of attack. In the firestorm ignited by the Ruddy revelation, the White House didn't deny that Trump was contemplating dumping Mueller – instead it claimed "while the President has the right to [fire Mueller], he has no intention to do so".

Another wrinkle for the Trump camp emerged on Thursday when Richard Burt, a Washington-based lobbyist for Russian interests, revealed that during the 2016 election campaign Sessions had asked him to help in formulating national security and foreign policy – inviting him to two dinners in the process. Burt's revelation that "I did attend two dinners with groups of former Republican foreign policy officials and Senator Sessions" seemed to contradict Sessions' insistent claim while testifying earlier this week that he had not had any other contact "with any representative, including any American lobbyist or agent of any Russian company" during the 2016 campaign. "I don't believe so," Sessions said in response to the specific question from Arizona Senator John McCain. Sessions irked Trump when he recused himself from any Justice Department consideration of the Russia investigation in March, after it was revealed that he had two meetings with Russian officials that he had seemingly denied during his confirmation hearing. Trump is gambling on navigating what has become a multi-layered legal quagmire by resorting to the political attack strategy that worked for him during the election campaign. Talking points for Trump surrogates, being circulated by the Republican National Committee, argue bluntly that there was no obstruction of justice and that the only crime was the "inexcusable, outrageous, and illegal" leaks.

They also seek to use comments by Comey on Obama-era attorney-general Loretta Lynch ordering him to call the probe of Hillary Clinton's emails "a matter" instead of "an investigation" to deflect attention from Trump, arguing that here was a provable obstruction of justice - Comey "openly admitted that [Lynch] successfully influenced him". The talking points also push the argument rehearsed in Trump's Thursday tweets – that having failed to prove collusion between the Trump campaign and the Russians who meddled in the 2016 campaign, investigators were now trying to "save face" by shifting to the obstruction of justice probe. The talking points conclude: "When is this fishing expedition going to end so we can get back to the real issues that matter to Americans?" But legal observers see a pattern of conduct by Trump that warrants investigation for obstruction: He openly admitted that his irritation with the conduct of the FBI's Russia investigation was the reason he sacked Comey;

Comey told the Senate of Trump's demand for personal "loyalty", upon which his tenure as FBI director seemed to be conditional;

However Trump may have parsed his request for Comey to "let go" of the investigation into former national security adviser Michael Flynn, Comey said he took the President's words as a "direction … an order";

Trump boasted to Russian Foreign Minister Sergei Lavrov that in sacking the "nut job" Comey he had greatly reduced the pressure he had been feeling from the Russia investigation.

Further it seems that Trump had used Sessions and his deputy Rod Rosenstein, wittingly or not, to craft a cover story on the Comey sacking that was publicly demolished by Trump's "this Russia thing" comment in a TV interview. In congressional testimony, both Sessions and Rosenstein refused to detail their conversations with Trump; as have national intelligence director Daniel Coats and National Security Agency boss Mike Rogers. Rogers and Coats and a former Rogers deputy have agreed to be interviewed by Mueller's investigators. To win politically, Trump needs to win public opinion. He has his work cut out. A new Associated Press-NORC Centre for Public Affairs Research poll finds a clear majority of Americans believe their President did try to interfere with the Russia investigation – and only 22 per cent support his sacking of Comey.

The poll, conducted in the wake of Comey's Senate testimony, which drew a national TV audience of 19 million, shows that 68 per cent of Americans are at least "moderately" concerned that the Trump campaign might have had inappropriate connections with Russia. Another poll, by Gallup, confirms the historic nature of Trump's approval/disapproval ratings. Compared with five other first-term presidents by this point in their term, his are by far the worst – 36 per cent approval to 60 per cent disapproval, compared with Ronald Reagan [59 to 28]; George Bush snr [70 to 14]; Bill Clinton [37 to 49]; George Bush jnr [55 to 35]; and Barack Obama [59 to 34]. Loading And while Jimmy Carter, Reagan and Clinton never sank to 60 per cent disapproval, it took Bush snr almost 1300 days, and Bush jnr more than 1700 days in office to sink to that level. Trump has hit the mark in just 144 days.