If anyone knows what an imploding White House looks like, it’s John Dean, former counsel to Richard Nixon. In 1972, Dean helped orchestrate Nixon’s cover-up of Watergate — he was “the master manipulator,” according to the FBI. Later, he helped expose the scandal by serving as the star witness for the prosecution.

Since then, Dean has become a kind of expert on presidential overreach, writing several books on the subject, including Blind Ambition, a story of the final days inside the Nixon White House as it crumbled under the weight of Watergate.

Naturally, Donald Trump has occupied much of Dean’s attention in recent months. His Twitter feed is studded with strident — and occasionally alarmist — posts. “Donald Trump is in the process of trashing the American presidency,” he wrote a few weeks ago. “He is just getting started.”

A Trump presidency, he added this week, represents “the greatest national security threat to the USA in decades.”

The way the Trump presidency is beginning it is safe to say it will end in calamity. It is almost a certainty. Even Republicans know this! — John Dean (@JohnWDean) January 31, 2017

The fallout over the various Trump-Russia scandals is raising even more questions about the stability of this administration. The leaks, the confusion, the botched executive orders, the inconsistencies, the attacks on the press — it just keeps compounding.

I reached out to Dean by phone this week to talk about the disarray in the White House. “I'm surprised,” he told me, “that [Trump] didn't use the transition period to better prepare himself for the presidency. On another level, I'm not surprised because he's so ignorant of government and how it works.”

The parallels between Trump and Nixon are hard to miss. Both men seem to be combustible, insecure personalities with a penchant for power. As Dean described it:

Nixon and Trump are both authoritarian personalities. Nixon concealed his authoritarianism, kept it behind closed doors, and he probably wouldn't test as high as Trump on this front. But they're both authoritarian personalities; they both have a kind of bunker mentality, which leads to isolation and paranoia. Nixon was not volatile; he very seldom exploded, and it was controlled when he did. He was a slow seether. But there was never a slight in his life that he forgot, and Trump is absolutely the same in that respect. They both also tend to fetishize power — they like to show it off.

I asked Dean what distinguishes Trump from Nixon, and why their differences might matter in terms of how they govern:

It's totally conspicuous: Nixon had vast experience in government. He'd been in the House of Representatives; he had served in the Senate and as vice president. Importantly, he had considerable experience and knowledge before assuming the presidency. He also knew lots of people whose help he could solicit in helping run an administration.

Dean has no ties to the Trump administration, but he’s worked inside a tumultuous White House before. The current situation, he says, is both familiar and predictable:

They're totally consumed by scandal and bad optics. I tweeted weeks ago that [Trump] was going to be confronted with these kinds of leaks because of the kind of campaign he ran, because of his stance against the intelligence agencies. He asked for this kind of blowback, and now he's getting it. As for what it's like inside the White House right now, what I'm picking up is that there is a lot of confusion and panic. They can't figure out who they want to put where. For now they’re just putting out one fire after another.

He was right, too. Four days after Trump’s inauguration, Dean tweeted that the “Trump administration is going to leak and leak and then some more — driving Donald crazy. Just stay tuned. I promise it will happen.”

Trump Administration is going to leak and leak and then some more -- driving Donald crazy. Just stay tuned. I promise it will happen. https://t.co/XlnnBfgE70 — John Dean (@JohnWDean) January 24, 2017

Dean still thinks the Trump presidency will “end in calamity,” though he’s not sure how or when. “His presidency is a massive skyscraper built atop a shifty foundation — it has to come down at some point,” he told me. By “shifty,” he means slippery and haphazard, a makeshift operation without a coherent vision or plan.

Trump can survive four years in office if he manages to keep the Republican-controlled Congress in line. But Trump, being who and what he is, will make it difficult for Republicans. He simply can’t help himself, Dean said. “It’s obvious that his presidency is vulnerable, and yet he keeps creating those vulnerabilities every day. Like Nixon, he’s a slave to his own worst instincts.”

But, Dean added, “Trump is more volatile.”