Washington - With Donald Trump and the news media unable to agree even on the weather, the war over truth is on.In the first few days of his presidency, Trump and his aides have been accused of spreading outright lies. The response: the "dishonest" media is out to get him.Since the weekend, Trump has been embroiled in controversy over the crowd at his swearing-in, with both he and the White House overstating its size - and dismissing conflicting evidence as biased against him.New York Times fact-checkers called out Trump for claiming the rain stopped and the weather turned "sunny" after his inaugural speech - noting that in reality, a light rain fell throughout his remarks.The same day, Trump falsely asserted that his well-documented feud with the US intelligence services was made up by the media.And two days later, on Monday, he told congressional leaders that as many as five million people could have voted illegally in November - a claim backed by no public evidence.During his campaign, Trump's loose interpretation of truth kept fact-checkers working around the clock - PolitiFact found 70% of his statements "mostly" false or worse.His first steps in the White House have followed a similar pattern: as news organisations called out the several falsehoods uttered over the weekend, his aide Kellyanne Conway defended what she called "alternative facts" - leaving much of America speechless.Trump spokesman Sean Spicer, in his first official media briefing on Monday, claimed that much of the press is opposed to the new president and itself fudges facts.He cited one report - which turned out to be inaccurate and was later corrected - indicating a bust of Martin Luther King Jr. had been removed from its place in the White House."Over and over again there's this constant attempt to undermine his credibility and the movement that he represents," Spicer said."And it's frustrating for not just him, but I think so many of us that are trying to work to get this message out. "Spicer appeared to soften the tone, calling for an improved relationship with journalists after Trump, on his first day in office, dubbed them "among the most dishonest human beings on Earth."Full OrwellBut at next day's briefing, Spicer stood by Trump's unsubstantiated claims of voter fraud, called out as a "lie" by leading media including the New York Times.Spicer told reporters the president "has believed that for a while based on studies and information he has," without giving evidence.Trump has previously cited two studies documenting voter registration errors, neither of which makes any claims about fraudulent voting.Summing up the view of many stunned observers, Washington Post media columnist Margaret Sullivan wrote this week that Spicer was sent to "brazenly lie" from the White House podium."We've gone full Orwell," she wrote, drawing a parallel to the distortion of facts in the dystopian classic "1984" - sales of which have spiked since the weekend.In these tussles over facts, some commentators see a deliberate strategy of delegitimizing the press, in order to curtail future scrutiny of the new administration."His war isn't with the media. Trump lives off media attention and delights in press coverage. His war is with facts," argued Vox.com editor-in-chief Ezra Klein."The Trump administration is creating a baseline expectation among its loyalists that they can't trust anything said by the media. The spat over crowd size is a low-stakes, semi-comic dispute, but the groundwork is being laid for much more consequential debates over what is, and isn't, true."Credibility at stakeStony Brook University political scientist John Ryan said the new administration appears to understand that increasingly, "in politics, the facts do not matter".Ryan, in a CNBC column, said many people believed unemployment went up under president Barack Obama when the opposite was true."The Trump administration knows this and believes it allows them to say whatever they want," Ryan said. "Because the facts will not play much of a role in how the public view his administration."Some analysts warn, however, that Trump's apparent willingness to bend facts is eroding his credibility, and could durably undermine trust in the US government."While I am much more concerned about policy than I am about crowd-size controversies, White House credibility is of paramount importance," said Andy Wright, a law professor and former White House staffer under Bill Clinton, writing for the Just Security blog."The Trump presidency has already ignited a crisis of confidence," he said."Without a credible White House, our allies cannot rely on our promises and our adversaries doubt our threats. Everything gets more dangerous."