In his first few days in the White House, the President and his advisers took direct aim at the reporters who are covering them. Standing in the headquarters of the CIA, President Trump decided to devote much of his remarks to assailing journalists.

"I have a running war with the media. They are among the most dishonest human beings on earth, right?" And press secretary Sean Spicer used his first White House briefing as an opportunity to attack the media falsely for understating the size of the crowds at Trump's inaugural ceremony.

"Some members of the media were engaged in deliberately false reporting," Spicer said. He warned that "This kind of dishonesty in the media, the challenging -- that bringing about our nation together is making it more difficult."

In an interview with NBC's "Meet the Press" the next day, Trump adviser Kellyanne Conway rejected Chuck Todd's assertion that the administration's crowd-size claims were a "falsehood" by saying that Spicer's numbers were legitimate "alternative facts." Trump told a group of legislators that fraudulent votes by illegal immigrants cost him the popular vote, a falsehood repeated by Spicer.

These tussles come after a long presidential campaign in which Trump attacked the media as an institution that was "rigged" against him. At some rallies, some Trump supporters even yelled a term used by the Nazis, "Lugenpresse" (translation: lying press), at media staff members.

This is not the first time that we have seen presidents going after the media. There were open attacks against journalists by President Richard Nixon and Vice President Spiro Agnew, who called the media the "nattering nabobs of negativism." Nixon even kept journalists like Daniel Schorr on a secret "enemies list." Most presidents, as Eric Alterman has reminded us in his classic account of presidential fabrication, "When Presidents Lie," deceive reporters and the public.

Lyndon Johnson hid from reporters his plan to escalate the war in Vietnam when he was questioned about the future of US involvement in Southeast Asia during the 1964 election. President Nixon secretly bombed Cambodia, while President Ronald Reagan's National Security Council conducted an elaborate operation of selling weapons to Iran and using the proceeds to fund the Nicaraguan Contras that they continually insisted to reporters they were not doing.

At a much smaller scale, President Bill Clinton did the same. "I did not have sexual relations with that woman," Clinton said of Monica Lewinsky, even though he did. President George W. Bush said there was solid evidence of weapons of mass destruction being in Iraq. There wasn't.

But the current assault against the media seems qualitatively different. This administration, armed with a new way to communicate directly to the public through social media, has started to conduct a multi-front war to systematically undermine the ability of the press to fulfill its responsibilities as a watchdog on government and as the main source of information for political news.

Trump will continue to directly attack the legitimacy of the news media, a theme that reverberates powerfully with his supporters. Throughout the campaign, and the first few days of the presidency, Trump and his advisers have continued to claim that the press is not a legitimate source of information.

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Reporters are biased against him, he says, and mainstream television and print outlets propagate "fake news." He's praised Fox News , whose prime-time opinion hosts back him, and criticized CNN.

The president has immense power to sow doubts with the public over the legitimacy of an institution. Whenever there has been an apparent media slip-up in the first few days, such as one report, soon corrected, that Trump had removed the bust of the Rev. Martin Luther King from the Oval Office, the White House jumped to claim that reporters could not be trusted. In the ultimate form of Kabuki theater, the ultimate disseminator of false information is pointing his finger at others.

The Trump White House is also intent on spreading its own alternative narrative about events to counteract whatever the media has to say. In a striking moment during a meeting with a bipartisan group of congressional leaders, Trump reasserted his claim that voter fraud by unauthorized immigrants had cost him the popular vote.

This was a more dangerous claim, one that fuels the drive for voter restrictions, than the "alternative facts" about crowd size. We can expect to see lying as a continued strategy for the White House, given how Trump ran his campaign.

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The President will simply make his own assertions about events, whether true or not, in order to undercut what reporters are saying. If the media zeroes in on a problem that he is facing, he will try to spin the story his own way.

Given Trump's power as President and his skill as the consummate showman, the press will have to figure out how to respond when they find themselves in a direct competition with the White House over telling the story of our times. They will also need to determine when the White House is creating simply a distraction to keep the press focused on the president's outrageous claims while more serious policy decisions are happening on Capitol Hill that require careful attention from reporters.

Attacking reporters, producers and news organizations directly also will be part of this war. We saw this ominously in the final weeks of the campaign when Trump paused in the middle of a rally to call out Katy Tur of NBC for underreporting the size of the crowds at his rally. There were reports that she needed protection after the crowd was incited.

During the transition, Trump castigated television news officials at a meeting in the Trump Tower for their coverage of the campaign. When CNN's Jeff Zeleny aired a segment challenging his allegations about massive voting fraud, he retweeted tweets accusing Zeleny of bring a bad journalist and went on to condemn CNN generally.

At a press conference, Trump refused to call on CNN's Jim Acosta after telling him "You are fake news" and saying he wouldn't answer questions from the organization. While speaking at the CIA, he called out Time magazine's Zeke Miller to attack him for his story about the King bust, even though Miller had corrected the mistake a day earlier.

As Trump ramps up these attacks, there is also the danger for journalists that he will goad them into the exact kind of behavior he is accusing them of doing. Without any question, more and more journalists have been unsettled by the tone of the administration and the attacks that have been coming their way.

The good news is that more journalists have become more determined to call events as they are, and this is a change in a positive direction. Within his first week as President, The New York Times published two dramatic headlines -- one saying that "Trump Repeats Lie About Popular Vote in Meeting with Lawmakers" and the other saying that "With False Claims, Trump Attacks Media on Turnout and Intelligence Rift."

But the danger would be for journalists to have a difficult time keeping a clear eye and avoiding openly partisan and openly biased work about a president they come to see as an opponent rather than the subject.

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Of course, the press is far from perfect. Parts of the media focus on trivial issues or give politicians a platform for provocative statements without seriously examining what they say. And the media is under economic pressure, with newspapers in particular cutting back on staffing and coverage due to an eroding advertising base.

The press has become more partisan in recent decades with the expansion of cable television and the end of the Fairness Doctrine.

Worst of all, public trust in the media has plummeted in recent years. According to a Gallup poll released in September, only 32% expressed "a great deal" or a "fair amount" of trust in the media; only 14% of Republicans shared that sentiment. This was a striking contrast to 1976, when in the aftermath of Watergate, trust and confidence in the media was at 72%.

But the flaws and problems of the press don't make the threat posed by a hostile administration any less urgent.

In the end, the press continues to serve a vital function in our polity as a guardian of democracy. We depend on the news media to provide the most accurate accounts of what is going on in Washington, in the statehouses and in the streets. Americans rely on reporters helping to prevent the abuse of power and to filter fact from fiction in an era when the barriers against the dissemination of information have been almost completely torn down.

This moment of challenge can thus turn into an opportunity -- just as journalists remade their profession in the Progressive Era when confronted by rampant political corruption, or in the 1960s and 1970s after Vietnam and Watergate exposed the urgency of tougher investigative reporting.

Never has the need for good journalism been more evident. Never has there been more need for media companies and nonprofit organizations to invest money in sound and careful reporting. With a President saying that everything the press does is irrelevant and wrong, it's time for it to step up and prove to the public just how wrong he is.