Republicans are said to be very worried.

When Robert Mueller in May 2017 embarked on his investigation into Russia’s alleged interference in the 2016 election and possible collusion with the Trump campaign, the president assembled a large team of high-profile DC lawyers to advise him about dealing with the special counsel.

Yet, as various Democratic-controlled committees in the House of Representatives push on with their probes, issuing subpoenas and calling on officials to testify, Mr Trump appears to have taken on the role of his own defence lawyer, shouting down anyone who dares to question him. Matt Mackowiak, a Republican operative and president of the Potomac Strategy Group, said Republicans would “rather not have to go through this”, though claimed the president may emerge stronger as his base was being energised.

“So far, Republicans are sticking with him,” he told The Independent. “At the moment there are no cracks.” Privately, some Republicans appear less confident. “Who knows what playbook they are on,” one Republican legislator told The Hill. “[Trump’s] pulling it out of his ass as he goes along.”

Everyone Trump has fired or forced out Show all 13 1 /13 Everyone Trump has fired or forced out Everyone Trump has fired or forced out John Bolton Trump claimed to have fired Bolton, his national security adviser, while Bolton claimed he offered to resign. An anonymous White House source that Bolton's departure came as a result of the national security adviser working too independently of the president AFP/Getty Everyone Trump has fired or forced out Anthony Scaramucci Scaramucci lasted only six days in his role as Trump's communications director before being fired by John Kelly, the incoming chief of staff Getty Everyone Trump has fired or forced out Rick Perry Rick Perry announced his resignation just as he became embroiled in the president's impeachment scandal. The White House said Mr Perry was asked by Donald Trump to work with Rudy GIuliani in regards to Ukraine. AP Everyone Trump has fired or forced out Rex Tillerson Tillerson, Trump's first secretary of state, was fired after a series of clashes with the president over policy Getty Everyone Trump has fired or forced out James Mattis Mattis served as secretary of defense from the beginning of Trump's administration until retiring on 1 January 2019. However, the president later claimed that he had "essentially fired" Mattis Getty Everyone Trump has fired or forced out James Comey Comey was fired as director of the FBI early in Trump's presidency after serving in the role for four years prior. His dismissal is widely thought to have been related to the Russia investigation Getty Everyone Trump has fired or forced out Reince Priebus Priebus, Trump's first chief of staff, was forced out after six tumultuous months AFP/Getty Everyone Trump has fired or forced out David Shulkin Veterans affairs secretary Shulkin claims that he was fired, the White House claims that he resigned Getty Everyone Trump has fired or forced out John Kelly Kelly, Trump's second chief of staff, was forced out after 17 months in office. His departure was a confused affair though it is clear that Trump wanted Kelly out AFP/Getty Everyone Trump has fired or forced out Michael Flynn Flynn lasted 24 days as Trump's national security adviser before being fired for lying to the FBI Getty Everyone Trump has fired or forced out Lee Cisna Cisna served as director of citizen and immigration services between October 2017 and June 2019 before being asked to resign amid a major personnel change in the department of homeland security Everyone Trump has fired or forced out Madeline Westerhout Westerhout served as Trump's personal assistant after leaking private information about his family AFP/Getty Everyone Trump has fired or forced out Mira Ricardel Ricardel was forced out of her role as Deputy National Security Advisor after first lady Melania Trump publicly called for her to be fired

The ways Trump has tried to defend himself:

Intimidation and threat

In what might be termed the “sicilian defence”, the president has shouted and made lots of noise, seeking to frame himself as the victim. He has used social media and appearances with foreign media to claim Democrats and their hidden helpers are seeking to carry out a “coup”. He referred to the “civil war” when tweeting about how supporters would feel if he were impeached. At the same time, he has sent out the likes of Mike Pompeo to attack Democrats on his behalf. Lawyers for the Ukraine whistleblower expressed concern for their client’s safety after the president said he wanted to see his accuser face to face. Mr Trump has hinted darkly at what should happen to the whistleblower and the people who gave him information, telling a private meeting of UN staff: “You know what we used to do in the old days when we were smart, right? The spies and treason, we used to handle it a little differently than we do now.”

However, this approach only takes the president so far. He may have got away with shouts and threats all his life, and for much of his political career, but there appears to be some steel and determination about Nancy Pelosi, the speaker of the House of Representatives, and her colleagues, that was not there before the Ukraine scandal erupted. Control of the house gives Democrats huge power. An impeachment probe is not something that can be bought off, hushed up or settled out of court.

Dismiss accusations as second or third-hand

The president has repeatedly sought to discredit the whistleblower. As well as suggesting they are a “spy”, he tweeted: “Fake Whistleblower complaint is not holding up. It is mostly about the call to the Ukrainian President which, in the name of transparency, I immediately released to Congress & the public. The Whistleblower knew almost nothing, its 2ND HAND description of the call is a fraud.” Whether the information raised by the whistleblower is first-hand, is not important. What matters is whether it is credible, something the intelligence community inspector general Michael Atkinson, among others, said it was. Veteran Republican senator Chuck Grassley said the whistleblower had acted correctly, adding: “No one should be making judgments or pronouncements without hearing from the whistleblower first and carefully following up on the facts.”

Claim transcript shows that conversation with Ukraine’s president was ‘beautiful’

The president has repeatedly said his conversation with his Ukraine counterpart contained nothing nefarious. “It was a beautiful, warm, nice conversation.” However, even the redacted partial memo released by the White House – not a transcript as the administration termed it – largely mirrors the whistleblower complaint. “The other thing, there’s a lot of talk about Biden’s son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the attorney general would be great,” the memo reports the president as saying. “Biden went around bragging that he stopped the prosecution, so if you can look into it.”

Mr Trump also moves on from discussing military aid to Ukraine – something Volodymyr Zelensky would have known had been suddenly suspended – to saying, “I would like you to do us a favour though”, and then asking him to get involved in investigations.

Claim Adam Schiff met the whistleblower

The president has frequently seethed about Democratic congressman Adam Schiff, chair of the House Intelligence Committee. He claimed Mr Schiff met the whistleblower to discuss the complaint. “He helped write it too,” Mr Trump said during a press conference with the president of Finland. Yet, while The New York Times reported than an aide of Mr Schiff may have received an outline of what the whistleblower would roughly allege the day before it was filed, the congressman claims to have maintained a degree of distance. A spokesperson told Fox News that Mr Schiff himself “does not know the identity of the whistleblower, and has not met with or spoken with the whistleblower or their counsel”.

Rudy Giuliani contradicts himself after claiming he would not cooperate with impeachment investigation

Claim Adam Schiff made up conversation in hearing

The president claimed the Democrat should be investigated for “treason” over remarks he made during testimony from Joseph Maguire, the acting director of national intelligence. He tweeted: “Adam Schiff illegally made up a FAKE & terrible statement, pretended it to be mine as the most important part of my call to the Ukrainian President ... Arrest for Treason?”

While the congressman parodied the president – “We’ve been very good to your country. Very good. No other country has done as much as we have. But you know what? I don’t see much reciprocity here. I hear what you want. I have a favour I want from you, though. And I’m going to say this only seven times, so you better listen good. I want you to make up dirt on my political opponent, understand?” – he claimed he was seeking to provide “the essence” of Mr Trump’s words.

He had prefaced his remarks by saying that the phone call “reads like a classic organised crime shakedown. Shorn of its rambling character and in not so many words, this is the essence of what the president communicates.”

Ironically the president himself regularly dramatises people’s words and sometimes seems to even be imagining conversations that appear unlikely to have taken place. Speaking to the media alongside the Finnish president in the Oval Office on Wednesday, he claimed that Nancy Pelosi had secretly been so impressed by the transcript of Mr Trump’s Ukraine call that she had regretted launching impeachment proceedings. Mr Trump said: “So when she saw that, she was – she – I heard she went crazy. She said, ‘We can’t impeach him on this conversation. That’s a great conversation.’”

President says he is frustrated at Europe doing nothing in Ukraine

Amid accusations that he is freezing military aid to Ukraine as a means of leverage, Mr Trump has insisted he merely wants other countries to pay more. “Why is it always the United States spending money,” he asked while appearing with Polish president Andrzej Duda at a meeting at the UN. “I don’t like it that it’s only us.” Many commentators have pointed out that that claim is not true. In July, the EU committed to spending €​100m to assist “accountable and efficient governance”. Since 2014, the EU has provided development cooperation totalling €​262.7m, while individual nations such as France have sent humanitarian aid.

President claims Biden and his son are corrupt

Mr Trump has said he is seeking to uncover wrongdoing by one of the Democratic contenders to take on the president next year. On Thursday, he urged China to launch its own probe. He said: “China should start an investigation into the Bidens because what happened in China is just about as bad as what happened with Ukraine.” Yet Joe Biden has denied any wrongdoing, and there is as yet no evidence to support the president’s claims. Yuri Lutsenko, a former top prosecutor in Ukraine, said he repeatedly rebuffed requests by Rudy Giuliani to launch a probe. He told the Los Angeles Times: “I told him I could not start an investigation just for the interests of an American official.” Meanwhile, the former US special envoy to Ukraine, Kurt Volker, reputedly testified on Capitol Hill that he had told Mr Giuliani the claims about Mr Biden’s corruption “were not credible”.

Get the vice president to speak on your behalf

Mike Pence has insisted he did not talk about Mr Biden when he spoke with the Ukrainian president in July. He also said the accusations against the former Democratic vice president needed to be examined. “One of the main reasons we were elected in Washington, DC, was to drain the swamp,” said Mr Pence, who added the president had said nothing wrong in his 25 July conversation. It is unclear, however, just how much in the loop Mr Trump kept his deputy. While it is known Mike Pompeo was on that call, CNN said Mr Pence was not, and was only told about it the following day.

Trump claims Biden sacked a prosecutor who was investigating his son

The president has claimed that Mr Biden, while involved in reforms in Ukraine after the ousting of the Kremlin-backed president Viktor Yanukovych, pushed to fire a prosecutor who was looking into corruption cases, including an allegation involving Burisma Holdings, the company that employed the then-vice president’s son. Yet reports suggest the firing of then-chief prosecutor Viktor Shokin was done because he was seen not to be doing enough to stop corruption, and that it came as part of a wider western effort to demand cleaner politics in return for international aid. Some reports suggest Mr Shokin was even standing in the way of probing Burisma, and there were no active investigations at the time of Mr Shokin’s departure in 2016.

Trump claims Hunter Biden took $1.5bn out of China

When he announced to the world he believed both China and Ukraine should investigate the Bidens, he did not mince his words. “Biden is corrupt, his son is corrupt,” he said. “His son takes out billions of dollars, billions, and he has no experience.” Yet, as with the Bidens’ involvement in Ukraine where there were also bad optics – Hunter Biden flew to China in 2013 aboard Air Force Two while his father made an official visit – the accusation that Hunter Biden made vast sums from his father’s role is not supported by facts. The New York Times reported in 2014 that a Shanghai-based private-equity company, BHR Equity Investment Fund Management, on whose board Hunter Biden had sat since 2013, said it was trying to raise $1.5bn. It said that in October 2017, after his father had left the vice presidency, he bought 10 per cent of the firm, investing the equivalent of $420,000. However, his lawyer George Mesires, told the newspaper this week that Hunter Biden has never been paid for his role on the board, and has not profited financially since he became a part-owner.