President Donald Trump’s lawyers set new conditions on Friday on an interview with the special counsel and said the chances that the president would be voluntarily questioned were growing increasingly unlikely.

The special counsel, Robert Mueller, needs to prove before Mr Trump would agree to an interview that he has evidence that Mr Trump committed a crime and that his testimony is essential to completing the investigation, said Rudy Giuliani, the president’s lead lawyer in the case.

His declaration was the latest sign that the president’s lawyers, who long cooperated quietly with the inquiry even as their client attacked it, have shifted to an openly combative stance.

Mr Giuliani acknowledged that Mr Mueller was unlikely to agree to the interview demands. Mr Mueller could subpoena Mr Trump to answer questions if he does not agree to voluntarily sit for an interview. Mr Giuliani left open the possibility that the president, who has said in the past that he would be eager to sit down with the special counsel, would still agree to be interviewed.

Mr Giuliani appeared to be in part trying to shift responsibility onto the special counsel for the lengthy negotiations over an interview — and was most likely prolonging them himself.

“If they can come to us and show us the basis and that it’s legitimate and that they have uncovered something, we can go from there and assess their objectivity," Mr Giuliani said. He urged the special counsel to wrap up his inquiry and write an investigative report. He said Mr Trump’s lawyers planned to write their own summary of the case.

A spokesman for the special counsel’s office declined to comment.

Giuliani: "Trump probably does have the power to pardon himself"

The president’s lawyers want Mr Mueller to explain how the Justice Department gave him the authority to investigate possible obstruction of justice by the president in what began as a counterintelligence investigation into Russia’s election meddling. The order appointing Mr Mueller authorised him to investigate possible links between Moscow’s interference and Trump associates, as well as any matters that arose from the inquiry.

The lawyers also want evidence that the special counsel exhausted every other investigative measure before asking the president to answer questions, and that he is the only person who could provide them with the information they are seeking.

The gambit by Mr Giuliani was the latest manoeuvre in an all-out assault by the president and his legal team in recent months to alter public opinion about the inquiry. They have come to believe that, if the Democrats win control of the House in November, the chamber will vote on whether to begin the impeachment process no matter the outcome of Mr Mueller’s investigation. So they want to sway Americans — and by extension, lawmakers.

To that end, Mr Trump has publicly complained about the investigation more frequently in recent months — tweeting about a “witch hunt” 59 times since March, compared with 20 times in all of 2017 — and Mr Giuliani regularly appears in the media attacking the investigation.

Mr Trump’s lawyers are quietly more combative, too, contesting a request from the special counsel to interview John F. Kelly, the White House chief of staff. Emmet T. Flood, the lead White House lawyer in dealing with the investigation, has demanded to know what investigators want to ask Mr Kelly and has tried to narrow the scope of their questions. A month after the request was made, Mr Kelly has not been questioned, though a White House official said he was willing to be.

“That’s the new position. If they had made the request eight months ago, they would have said yes because they thought there was a group of people on Mueller’s team who had an open mind and were objective,” Mr Giuliani said of the president’s previous lawyers, most of whom have left the legal team.

The effort appears to be bearing some fruit. According to a Washington Post-Schar School poll released on Friday, 45 percent of Americans disapprove of how Mr Mueller is handling the investigation, a 14-point increase from January.

“Nobody is going to consider impeachment if public opinion has concluded this is an unfair investigation, and that’s why public opinion is so important,” Mr Giuliani said.

The strategy is a departure from the legal team’s playbook during the first year of the special counsel investigation, when Mr Trump’s lawyers were more cooperative. They waived executive privilege, handed over documents and made White House aides available for interviews, convinced that it would hasten the end of the inquiry.

But in April, Mr Trump concluded that Mr Mueller and Justice Department officials were determined to find wrongdoing after federal investigators in New York, acting on a referral from the special counsel, raided the office, hotel room and home of Mr Trump’s longtime personal lawyer Michael D. Cohen.

After the raid, Mr Trump decided to double down on his more aggressive strategy, according to people close to him. He hired Mr Giuliani to replace his lawyer John M. Dowd, who had convinced Mr Trump of the value of the earlier, more cooperative approach. Mr Giuliani immediately began a public relations assault on Mr Mueller. Mr Flood, who is known for his strong view of the president’s powers to shield his communications and documents from investigators, was brought on in May.

The biggest names involved in the Trump-Russia investigation Show all 17 1 /17 The biggest names involved in the Trump-Russia investigation The biggest names involved in the Trump-Russia investigation Paul Manafort Mr Manafort is a Republican strategist and former Trump campaign manager. He resigned from that post over questions about his extensive lobbying overseas, including in Ukraine where he represented pro-Russian interests. Mr Manafort turned himself in at FBI headquarters to special counsel Robert Mueller’s team on Oct 30, 2017, after he was indicted under seal on charges that include conspiracy against the United States, conspiracy to launder money, unregistered agent of a foreign principal, false and misleading US Foreign Agents Registration Act statements, false statements, and seven counts of failure to file reports of foreign bank and financial accounts. Getty The biggest names involved in the Trump-Russia investigation Rick Gates Mr Gates joined the Trump team in spring 2016, and served as a top aide until he left to work at the Republican National Committee after the departure of former Trump campaign manager Paul Manafort. Mr Gates' had previously worked on several presidential campaigns, on international political campaigns in Europe and Africa, and had 15 years of political or financial experience with multinational firms, according to his bio. Mr Gates was indicted alongside Mr Manafort by special counsel Robert Mueller's team on charges that include conspiracy against the United States, conspiracy to launder money, unregistered agent of a foreign principal, false and misleading US Foreign Agents Registration Act statements, false statements, and seven counts of failure to file reports of foreign bank and financial accounts. AP The biggest names involved in the Trump-Russia investigation George Papadopoulos George Papadopoulos was a former foreign policy adviser for the Trump campaign, having joined around March 2016. Mr Papadopoulos plead guilty to federal charges for lying to the FBI as a part of a cooperation agreement with Special Counsel Robert Mueller's investigation. Mr Papadopoulos claimed in an interview with the FBI that he had made contacts with Russian sources before joining the Trump campaign, but he actually began working with them after joining the team. Mr Papadopoulos allegedly took a meeting with a professor in London who reportedly told him that Russians had "dirt" on Hillary Clinton. The professor also allegedly introduced Mr Papadopoulos to a Russian who was said to have close ties to officials at the Russian Ministry of Foreign Affairs. Mr Papadopoulos also allegedly was in contact with a woman whom he incorrectly described in one email to others in the campaign as the "niece" to Russian President Vladimir Putin. Twitter The biggest names involved in the Trump-Russia investigation Donald Trump Jr The President's eldest son met with a Russian lawyer - Natalia Veselnitskaya - on 9 June 2016 at Trump Tower in New York. He said in an initial statement that the meeting was about Russia halting adoptions of its children by US citizens. Then, he said it was regarding the Magnitsky Act, a US law blacklisting Russian human rights abusers. In a final statement, Mr Trump Jr released a chain of emails that revealed he took the meeting in hopes of getting information Ms Veselnitskaya had about Hillary Clinton's alleged financial ties to Russia. He and the President called it standard "opposition research" in the course of campaigning and that no information came from the meeting. The meeting was set up by an intermediary, Rob Goldstone. Jared Kushner and Paul Manafort were also at the same meeting. Getty Images The biggest names involved in the Trump-Russia investigation Jared Kushner Mr Kushner is President Donald Trump's son-in-law and a key adviser to the White House. He met with a Russian banker appointed by Russian President Vladimir Putin in December. Mr Kushner has said he did so in his role as an adviser to Mr Trump while the bank says he did so as a private developer. Mr Kushner has also volunteered to testify in the Senate about his role helping to arrange meetings between Trump advisers and Russian Ambassador to the US Sergey Kislyak. Getty Images The biggest names involved in the Trump-Russia investigation Rob Goldstone Former tabloid journalist and now music publicist Rob Goldstone is a contact of the Trump family through the previously Trump-owned 2013 Miss Universe pageant, which took place in Moscow. In June 2016, he wrote to Donald Trump Jr offering a meeting with a Russian lawyer, Natalya Veselnitskaya, who had information about Hillary Clinton. Mr Goldstone was the intermediary for Russian pop star Emin Agalaraov and his father, real estate magnate Aras, who played a role in putting on the 2013 pageant. In an email chain released by Mr Trump Jr, Mr Goldstone seemed to indicate Russian government's support of Donald Trump's campaign. AP images The biggest names involved in the Trump-Russia investigation Aras and Emin Agalarov Aras Agalarov (R) is a wealthy Moscow-based real estate magnate and son Emin (L) is a pop star. Both played a role in putting on the previously Trump-owned 2013 Miss Universe pageant in Moscow. They allegedly had information about Hillary Clinton and offered that information to the Trump campaign through a lawyer with whom they had worked with, Natalia Veselnitskaya, and music publicist Rob Goldstone. Getty Images The biggest names involved in the Trump-Russia investigation Natalia Veselnitskaya Natalia Veselnitskaya is a Russian lawyer with ties to the Kremlin. She has worked on real estate issues and reportedly counted the FSB as a client in the past. She has ties to a Trump family connection, real estate magnate Aras Agalarov, who had helped set up the Trump-owned 2013 Miss Universe pageant which took place in Moscow. Ms Veselnitskaya met with Donald Trump Jr, Jared Kushner, and Paul Manafort in Trump Tower on 9 June 2016 but denies the allegation that she went there promising information on Hillary Clinton's alleged financial ties to Russia. She contends that the meeting was about the US adoptions of Russian children being stopped by Moscow as a reaction to the Magnitsky Act, a US law blacklisting Russian human rights abusers. Getty Images The biggest names involved in the Trump-Russia investigation Mike Flynn Mr Flynn was named as Trump's national security adviser but was forced to resign from his post for inappropriate communication with Russian Ambassador to the US Sergey Kislyak. He had misrepresented a conversation he had with Mr Kislyak to Vice President Mike Pence, telling him wrongly that he had not discussed sanctions with the Russian. Getty Images The biggest names involved in the Trump-Russia investigation Sergey Kislyak Mr Kislyak, the former longtime Russian ambassador to the US, is at the centre of the web said to connect President Donald Trump's campaign with Russia. Reuters The biggest names involved in the Trump-Russia investigation Roger Stone Mr Stone is a former Trump adviser who worked on the political campaigns of Richard Nixon, George HW Bush, and Ronald Reagan. Mr Stone claimed repeatedly in the final months of the campaign that he had backchannel communications with WikiLeaks founder Julian Assange and that he knew the group was going to dump damaging documents to the campaign of Democratic candidate Hillary Clinton - which did happen. Mr Stone also had contacts with the hacker Guccier 2.0 on Twitter, who claimed to have hacked the DNC and is linked to Russian intelligence services. Getty Images The biggest names involved in the Trump-Russia investigation Jeff Sessions The US attorney general was forced to recuse himself from the Trump-Russia investigation after it was learned that he had lied about meeting with Russian Ambassador to the US Sergey Kislyak. Getty Images The biggest names involved in the Trump-Russia investigation Carter Page Mr Page is a former advisor to the Trump campaign and has a background working as an investment banker at Merrill Lynch. Mr Page met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republican National Convention in Cleveland. Mr Page had invested in oil companies connected to Russia and had admitted that US Russia sanctions had hurt his bottom line. Reuters The biggest names involved in the Trump-Russia investigation Jeffrey "JD" Gorden Mr Gordon met with Russian Ambassador to the US Sergey Kislyak during the 2016 Republian National Convention to discuss how the US and Russia could work together to combat Islamist extremism should then-Republican presidential candidate Donald Trump win the election. The meeting came days before a massive leak of DNC emails that has been connected to Russia. Creative Commons The biggest names involved in the Trump-Russia investigation James Comey Mr Comey was fired from his post as head of the FBI by President Donald Trump. The timing of Mr Comey's firing raised questions around whether or not the FBI's investigation into the Trump campaign may have played a role in the decision. Getty Images The biggest names involved in the Trump-Russia investigation Preet Bharara Mr Bahara refused, alongside 46 other US district attorney's across the country, to resign once President Donald Trump took office after previous assurances from Mr Trump that he would keep his job. Mr Bahara had been heading up several investigations including one into one of President Donald Trump's favorite cable television channels Fox News. Several investigations would lead back to that district, too, including those into Mr Trump's campaign ties to Russia, and Mr Trump's assertion that Trump Tower was wiretapped on orders from his predecessor. Getty Images The biggest names involved in the Trump-Russia investigation Sally Yates Ms Yates, a former Deputy Attorney General, was running the Justice Department while President Donald Trump's pick for attorney general awaited confirmation. Ms Yates was later fired by Mr Trump from her temporary post over her refusal to implement Mr Trump's first travel ban. She had also warned the White House about potential ties former National Security Adviser Michael Flynn to Russia after discovering those ties during the FBI's investigation into the Trump campaign's connections to Russia. Getty Images

Mr Giuliani has sown doubt and confusion by pushing dubious theories about the case. He has made claims like accusing Mr Mueller’s office, without evidence, of trying to frame Mr Trump. Mr Giuliani has also pushed unfounded theories, like an assertion that the FBI implanted a spy in Mr Trump’s campaign.

The president and his lawyers have also tried to undermine key witnesses like James B. Comey, the former FBI director fired by Mr Trump, to force the public to decide whether to believe them or the president. That is a tall task — the president’s penchant for half-truths, exaggerations and outright falsehoods is well established.

But Mr Trump and his lawyers contend that Mr Comey damaged his credibility as a witness during his book tour this spring by showing that he played by his own rules when he ran the FBI, and that the findings of a recent inspector general report critical of the FBI’s handling of the Hillary Clinton email investigation buttressed their case.

Mr Giuliani views the tactics as an early success. “Right now, public opinion is going in our direction big time,” he said.

His approach also extends to his public portrayal of the negotiations with Mr Mueller over a presidential interview. Even as they have delayed any agreement for at least six months of negotiations, the lawyers have condemned the special counsel for dragging out the inquiry, saying he has had more than enough time to complete his investigation.

Mr Giuliani has gone back and forth about whether the president will agree to be questioned and given varying timetables. He once said Mr Trump would make a decision after his meeting with the North Korean leader, Kim Jong Un, last month, then changed that deadline to July. The president’s lawyers have set other deadlines that came and went without resolution.

This stalling has all but dared Mr Mueller to subpoena Mr Trump to testify, potentially setting off a months-long battle in court about whether the president can be compelled to answer questions under oath.

Also prompting a shift in the president’s strategy was the conclusion by his lawyers that even if Mr Mueller finds evidence of wrongdoing, he will adhere to Justice Department memos that say the president should not be indicted, and is likely to instead send a damaging report on Mr Trump’s conduct to Congress.

Critics see the array of delay tactics as aimed at stalling an investigative report to Congress until after November’s midterm elections. The more time Mr Trump and his lawyers have to influence Americans’ views of the inquiry, the better their chances to undermine its credibility and pressure lawmakers not to impeach Mr Trump.

Legal experts are sceptical that the new tactics will be effective. “It’s a gambit because if there’s damaging information that comes out down the line — like primary source documents or testimony — then you’ve spent your capital trying to create a public narrative that is belied by hard evidence,” said Stephen I. Vladeck, a professor at the University of Texas School of Law and an expert on constitutional law.

Mr Dowd said the public did not appreciate the damage the investigation had done to both Mr Trump and the presidency over the past year. He said he had come around to Mr Trump’s view, first voiced by the president last summer, that Mr Mueller is acting in bad faith.

“That’s the way the president was at the beginning,” Mr Dowd said, “and the president was right.”