Historians and journalists are pointing out similarities between Donald Trump's approach to governing and the tactics of Richard Nixon, who became known for compiling lists of enemies and enveloping himself in an atmosphere of suspicion and enmity during his presidency from 1969 to 1974.

What is prompting the Nixon comparison is Trump's escalating barrage of criticism against his adversaries, especially the mainstream media. Last weekend, he told a rally in Melbourne, Florida, that the media have "their own agenda, and their agenda is not your agenda." On Friday, he tweeted that the New York Times, ABC, CBS, CNN and NBC are "the enemy of the American people," escalating his attacks. He called these outlets "the fake news media" and said they are out to get him.

He was blasted by media advocates and others. "Donald Trump is demonstrating an authoritarian attitude and inclination that shows no understanding of the role of the free press," said Carl Bernstein, the former Washington Post reporter who helped to reveal the Watergate scandal that forced Nixon to resign in 1974.

Rice University historian Doug Brinkley went further, telling The Associated Press: "There has never been a kind of holistic jihad against the news media like Trump is executing. Trump is determined to beat and bloody the press whenever he finds himself in a hole, and that's unique." Princeton historian Julian Zelizer said on CNN that all presidents experience tension with the press but "the scale and scope of this is unlike anything that we've seen in the past."

And Sen. John McCain, R-Ariz., who has tangled with Trump on other issues, told NBC, "That's how dictators get started. They get started by suppressing a free press. In other words, a consolidation of power. When you look at history, the first thing that dictators do is shut down the press. ... I'm not saying that President Trump is trying to be a dictator. I'm just saying we need to learn the lessons of history."

At a fiery news conference Thursday, Trump said, "Much of the media in Washington, D.C., along with New York, Los Angeles in particular, speaks not for the people, but for the special interests and for those profiting off a very, very obviously broken system."

Trump is incensed because news organizations have reported on his administration's mistakes, inconsistencies, falsehoods, lack of coordination and other problems, which is par for the course when a new president takes over. Last week, Trump demanded and got the resignation of his national security adviser Michael Flynn, who misled Vice President Mike Pence over Flynn's contacts with Russia. On Monday, Trump named Army Lt. Gen. H.R. McMaster as his new national security adviser. In addition, Trump's first nominee for labor secretary, Andrew Puzder, a fast-food chain executive, withdrew from consideration because of opposition in the Senate, and the president hastily named a replacement, Alexander Acosta, dean of Florida International University law school.

Trump has also been pilloried for issuing a confusing and far-reaching executive order to suspend immigration from seven Muslim-majority nations, an order that the courts have blocked, at least temporarily. Trump is working on a new executive order limiting immigration, which he is likely to unveil this week.

The Nixon comparisons are growing more stark. Bernstein told the New York Times, "There is a similarity in trying to divide the country and make the conduct of the press the issue instead of the conduct of the president." Bernstein said Trump's heightened rhetoric and all-out assault on the Fourth Estate "may be more insidious and dangerous than Richard Nixon's attacks on the press."

Trump's goal, his critics say, is to undermine the media's credibility so the public will no longer believe journalists' critiques of the Trump presidency.

Nixon authorized his vice president Spiro Agnew to blast the media in public, but Nixon tried to keep most of his own anti-media venom private.

However, Nixon's supporters wiretapped the phones of reporters whom they considered Nixon's opponents and whose conversations, the Nixon supporters believed, might indicate the source of damaging leaks.

During the rising frenzy over the Watergate scandal in 1973, Nixon told reporters at a news conference, "Don't get the impression that you arouse my anger. You see, one can only be angry with those he respects." Earlier, in December 1972, Nixon told his national security adviser Henry Kissinger, "The press is the enemy. The establishment is the enemy. The professors are the enemy," according to a tape of their conversation.