Morning mail: impeachment possible if Trump lied about Mueller Monday: Ken Starr, the special prosecutor who pursued Bill Clinton, says there could be grounds for impeachment. Plus: Turnbull aims to boost arms exports Donald Trump speaks to Congress. Photograph: Jim Lo Scalzo/AP Eleanor Ainge Roy @EleanorAingeRoy Good morning, this is Eleanor Ainge Roy bringing you the main stories and must-reads on Monday 29 January. Top stories If Donald Trump lied to the American people when he called reports he tried to fire Robert Mueller "fake news", that would be grounds for impeachment, the independent counsel who investigated the Clinton White House has said. Ken Starr, who used Bill Clinton's false statements about his relationship with Monica Lewinsky as grounds for impeachment, told ABC's This Week: "Lying to the American people is a serious issue that has to be explored." Some Republicans said on Sunday that reports Trump had to be talked down from firing Mueller were a serious concern and should prompt congressional action. The New York Times and others reported that in June Trump ordered the White House counsel, Donald McGahn, to fire Mueller. McGahn reportedly said he would resign rather than carry out the order, which he said would have a devastating effect on Trump's presidency. Trump dismissed the report, calling it "fake news". He has repeatedly denied that he was considering firing Mueller. Roger Federer has won his 20th grand slam title with a stunning Australian Open victory over Marin Cilic which brought the tennis legend to tears. Federer beat Cilic 6-2, 5-7, 6-3, 3-6, 6-1 in just over three hours under the roof on Rod Laver Arena – then the 36-year-old father of four broke down in tears at the end of the courtside presentation. . And Caroline Wozniacki has ended years of doubt with her maiden grand slam win, with the Dane saying she now has nothing to lose after beating Simona Halep in an epic final. Australia is set to become one of the world's largest arms exporters under a controversial Turnbull government plan. Malcolm Turnbull has unveiled a "defence export strategy", setting out the policy to make Australia one of the world's top 10 weapons exporters within the next decade. "A strong, exporting defence industry in Australia will provide greater certainty of investment, support high-end manufacturing jobs and support the capability of the Australian defence force," the prime minister said. The plan has been attacked by the World Vision Australia chief advocate, Tim Costello, as "exporting death". "There is only one purpose in making a weapon and that is to kill someone with it," Costello said. "Do we really want that to be what people think of when they see the brand 'made in Australia'?" The former Labor treasurer Wayne Swan says inequality is one of the biggest threats to Australia's way of life and has warned the country not to go down the same path as Trump's America. Swan said Scott Morrison's latest push for further company tax cuts, which would see the headline tax rate cut from 30% to 25%, would only serve to widen the growing gap between the rich and poor. Swan points to the US as an example of how it can all go wrong and says Australia should turn back before it's too late. Ten foreigners, including five British tourists and a New Zealander, have been arrested in Cambodia for "singing and dancing pornographically", after a raid on a party in Siem Reap near the tourist destination of Angkor Wat. They face up to a year in prison and could spend six months in detention before the case goes to court, according to reports. Cambodian police released images online that appeared to show clothed and laughing tourists imitating sexual positions. Sport The opening match at Perth's new Optus Stadium saw its first five-wicket haul courtesy of the five for 46 of Western Australia's own Andrew Tye, and even its first streaker. But it will have to wait a little longer for its first Australian win thanks to a virtuoso performance from Tom Curran, who bettered Tye with five for 35 and snuck England to a 12-run win in the fifth and final one-day international. Daniel Arzani is still a teenager but already towers over his Melbourne City team-mates from a statistical standpoint. Does City's coach, Warren Joyce, fully appreciate what a talent he has on his hands? Though Arzani is far from the finished article, when does a primary focus on what he can't do – as opposed to what he can – become stifling? Thinking time Tim Minchin. Photograph: Richard Saker for the Observer It has been a tough year for Australian polymath Tim Minchin, "unbearable", he says, of life under Trump and the collapse of his $100m movie. Minchin and his family have moved from Los Angeles to Sydney and in doing so escaped one of the biggest political upheavals in US history. "It's awful living there with Trump," he says. "I'm so glad I'm out of that country – I think it's really broken." A new start means new projects, including an upcoming ABC comedy, Squinters. Minchin talks to Steph Harmon about narcissicm, his lifelong apprenticeship and how the #MeToo movement is changing his industry. Before Trump's medical exam, 75 health professionals urged in an open letter to the presidential physician that he evaluate the president's neurological health – which Trump passed 30 out of 30. The president's dementia assessment and other specialist tests are available online, with the internet putting specialist knowledge into the hands of non-experts. The days of priestly castes of professionals are gone, and mostly for the better, but caution is still advised, writes the Guardian's readers' editor, Paul Chadwick. If there is a single economic policy that symbolises the dominant economic ideology of the decades from the 1970s to the global financial crisis, it's privatisation, writes the University of Queensland economist John Quiggin. For decades the public have been sold privatisation on the basis that it would provide finance for desirable public investments. It is striking that, given the near-universal political consensus in favour of neoliberalism, and particularly privatisation, that the public has never embraced this idea. Indeed, voters have become more resolutely hostile. What's he done now? Donald Trump has started a new feud, with the rap legend Jay-Z. In an interview on Saturday the singer rejected the idea that Trump had been good for African Americans, calling the president a "superbug" in a discussion of his reported racist remarks, including calling a number of African countries "shitholes". Overnight, Trump hit back on his favourite medium, saying: "Somebody please inform Jay-Z that because of my policies, Black Unemployment has just been reported to be at the LOWEST RATE EVER RECORDED!" Media roundup The Courier-Mail reports on underhand tactics allegedly used by some "rogue" Queensland funeral homes, including conducting mass cremations and chasing ambulances. The NT News splashes with the aftermath of a monsoonal storm that flooded Darwin streets, brought down gigantic trees and scattered debris across major roads. The ABC has a long read on Greenland, where people are embracing climate change. For many of its 56,000 residents, melting ice means money. Coming up Campaigning will begin in the Tasmanian election with the premier, Will Hodgman, heading to the the state's north and Labor's Rebecca White at Tullah on the west coast. Students return to school in South Australia, Victoria and the Northern Territory after the summer holidays. 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