Brace yourself for the most devastating market crash ever in “the greatest political and economic revolution since the advent of democracy.” That’s the dire alert from colorful, controversial prognosticator Harry S. Dent Jr., in an interview with ThinkAdvisor.

Dent, who chiefly uses demographic cycles to forecast the economy and markets, correctly predicted Japan’s 1989 economic collapse, the 2000 dot-com bust and the populist wave enabling Brexit and Donald Trump’s election.

Last June, Dent told ThinkAdvisor that an economic and stock market calamity would strike within three years. He is now indeed predicting the crash to occur between late 2017 and early 2020. But with only five weeks to go this year, if stocks don’t start tumbling soon, he’ll be rethinking that forecast, the usually adamant Dent says, with concern.

His new book, “Zero Hour: Turn the Greatest Political and Financial Upheaval in Modern History to Your Advantage,” written with Andrew Pancholi (Portfolio), raises a loud alarm about the 2020s, which, based mainly on four demographic and geopolitical cycles, will bring a ghastly global crisis, or what Dent terms the dark “Economic Winter,” he predicts.

Over three decades, Dent’s prophecies have been a mixed bag of hits and misses. Cautioning about a bubble that, he says, has been building for years, Dent, 65, now touts three “safe havens” in which to invest.

In the interview, he also discusses market sectors he expects to outperform in the terrible ’20s.

The Harvard MBA and founder of Dent Research publishes newsletters and investing strategy systems and has written a number of books that have either hyped a big boom ahead or warned of disaster on the brink. These works have included “The Sale of a Lifetime” (2017) and “The Demographic Cliff” (2015).

With Bain & Co. at the start of his career, Dent consulted to a range of Fortune 100 companies as well as startups.

ThinkAdvisor recently interviewed the so-called “Contrarian’s Contrarian,” who talked about, among other issues, the tax cut, why he expects investors to be fuming at their FAs and why the sunspot cycle (you read that correctly) is a valid predictor of market crashes. Here are excerpts from our conversation:

THINKADVISOR: In your new book, you say that a devastating crash will occur between late 2017 and early 2020. There are only five weeks left to 2017. Are you sticking with that time frame?

HARRY DENT JR.: We may be starting a topping process. I’m seeing signs of that, but it hasn’t yet been proven. We ought to see the market start to go down by early next year. If it doesn’t, I’m going back to the drawing board. If the market doesn’t start crashing by late January or early February, then we aren’t topping here. But we’re saying there’s going to be a crash. It’s just a matter of when [exactly].

Is that prediction despite, or because of, the bull market’s longevity?

So far, the market has gone up in bad news, threat of war; Trump’s saying the stupidest things known to humankind and [is under threat of] getting damn near impeached. The market still goes up because money has nowhere else to go. So stocks are the only game in town. They’re going to go till they blow, and it looks like they’re getting close to blowing.

At this point, what are you certain of?

The one thing I do know is that the market will make a major change in direction. It’s going to try to hide it as much as possible because it wants to screw everybody. The big traders — the sharks — make money, but all the minnows get eaten. That’s what the market wants. It wants people to be trapped in the bubble. Bubbles are very tricky to play. Now is a good time to get out. The upside is limited.

Why will a crash occur?

Simply because [the U.S. government] has kept putting off this crisis. And, of course, the more you allow bubbles to build up, the more excesses you have.

Please elaborate.

Instead of dealing with the global financial crisis of 2008, the government just printed a bunch of money and tried to blow their way out of it.  Central banks should be able to create money in line with the growth of the economy, period. Central banks only make bubbles worse, which means crises and depressions and the deleveraging that follows.

Just how bad will the next crisis be?

With the last one, we didn’t have a Great Depression, which is what our models are calling for. So we’re just going to get hit harder this time. Stocks won’t go down 50%; they’ll be down 70%-80%. Unemployment won’t be at 9% or 10%; it will be 15%.

How much are you considering the rally that began with Trump’s election?

This has been the biggest fake rally in history! Companies are buying back their own stupid-ass stock even if earnings aren’t growing. That’s ridiculous. Governments are buying their own bonds so they can keep stimulating. Trump says that everything is great, and we’re going to get a tax cut. Bull—-!

But the economy is buzzing along, isn’t it?

Every economy that ever peaked looked perfect at the top. The U.S. looked great in late 1929 before the Great Depression and the greatest crash in history. You have to look at the things that will projectably change: Demographics are projectable.

What are the demographics indicating to you now?

I’m mostly looking at the downward convergence of the four fundamental cycles: the generational spending wave, the geopolitical cycle, the 45-year innovation cycle and the boom/bust cycle. These directly affect spending, productivity, stock valuations and other aspects of the economy. They’re things that I can project and track.

So what do you see?

We don’t have demographic growth, even with stimulus and giving everybody a free lunch. And then there are the struggles in Europe: Italy is getting ready to blow. China is going to blow; and when China blows, there’ll be nothing that Europe, the U.S. and the central banks can do to offset it.

But what about Trump’s proposed tax cut?

It’s not going to create 4% [GDP] growth. Business might feel good for a couple of quarters, but there isn’t anything to build on. You can give companies a trillion dollars, but what are they going to do with it? Just buy back stock and pay dividends to their shareholders. They don’t need to expand. We’ve got excess supply here and around the world. We don’t need businesses to invest in a lot of new capacity. We already did that in the boom.

But what about generating more jobs?

There’s no work force to hire. Growth is basically zero. It will be twice as negative in years to come. We’re at full employment. We’re not going to get 4% growth because we cut taxes! This will not happen. Productivity has dropped to half a percent. And it’s going to keep dropping because baby boomers ain’t gettin’ any younger.

Well, do you think that the tax cut will benefit the middle class?

They’ll get some token cuts, but middle-class people don’t pay much in taxes. Income tax is already very low for the middle class and below. The primary tax they pay is on Social Security, and they’re not cutting that tax.

You disagree with experts who say that black swan events occur. Why do you think there’s no such thing?

The giant 1929 crash didn’t come out of nowhere. We’re saying there’s going to be a crash. When economists will say, “Well, nobody could have seen that coming,” I’m going to punch them all in the nose because they’re idiots. This is something you can totally see coming.

Why will economists say no one could have predicted it?

People are in denial because they’re getting a free lunch: the government, companies, individuals with lower-cost loans. They don’t want all that to end. They also know that when a bubble bursts, it’s going to be very bad — so they don’t want to hear somebody like me say that this is a bubble. But it’s so obvious that it’s unbelievable.

How do you know for sure we’re in a bubble?

All bubbles follow the trajectory of the male orgasm. And, look at the three bubbles we’ve had: the tech bubble, the 2007 bubble and the one we’re in now. They’re following the female triple-orgasm chart.

You write that your “new secret weapon” is sunspot cycles. That sounds iffy.

I get a lot of flak about that one. We’re in a down cycle now, and it won’t bottom till around early 2020. Demographics tell you when the economy will slow, but sunspots tell you when a crash or major stock correction is going to happen. We researched sunspot cycles, recessions and major financial crises as far back [as possible], and 11 out of 11 happened in a down sunspot cycle.

People “are going to hate most stockbrokers and financial advisors in the years ahead,” you write. Why would they?

Because stockbrokers tell people, “Don’t try to time the markets.” That works most of the time. But when you get a bubble of this magnitude, “Just hang in there — it will come back; we’ve got to diversify” isn’t going to help. This is a once-in-a-lifetime bubble-burst. Diversification didn’t work in 2008 because when bubbles burst, everything goes down except for cash, high-quality bonds and things like the U.S. dollar.

Is that what you have now?

That’s all we own. The safe havens are Treasuries, Triple-A corporate bonds and the dollar.

What’s the logic behind that strategy?

We may not reach new stock highs adjusted for inflation until long after I’m dead because for the first time in modern history our demographics won’t take us to new heights in the future.

What sectors in aging developed countries do you favor long-term?

Health and wellness, pharmaceuticals and vitamins, biotech and medical devices, cruise ships, funeral homes and nursing homes.  That’s all because of the baby boomers. They’re this long demographic force, but they won’t be spending on much outside of health care and travel. 

You write that “in the next global boom,” emerging countries will dominate and that India will be “the next China.”

No question about India, as long as they don’t screw it up, and they’re not screwing it up so far.

Why do you like emerging countries?

Southeast Asia, India, China, the Asian countries have a stronger productivity curve than Africa or South America. Indonesia is moving people from rural areas with very low-productivity jobs to urban areas, where there’s more specialized work that pays three times as much on average.

Why do you write that energy will likely be “underperforming for decades”?

Because they’ve got the frackers sitting on them. Every time oil gets back to $50 or $60, the frackers start cranking up again, and then they get excess supply. The Saudi princes are saying we’ll never see $100 oil again, and I agree — or at least not for a very, very long time. I see oil at pretty much between $20 and $60 for decades. And we won’t see natural gas at $14 again — because of fracking.

Why are you forecasting a commodities boom “by early 2020 or early 2023”?

Commodities are crashing the fastest; so they’re likely to turn around early. They’re driven more by emerging countries, which are big commodity producers, versus developed countries. I like industrial and precious metals, including gold, silver and platinum, because they’re scarce. They’ll outperform. You can’t just farm them like you can cows and pigs and corn and wheat, [for which] you can always expand into more land. But there’s only so much gold, platinum and other metals. I’m big on gold after it crashes.

You write that artificial intelligence won’t pay off for a few years.

Yes, but that doesn’t mean you can’t make money investing in it. It’s not going to cause a great productivity surge for the broad economy because such technologies are small and in niche markets. 

You’ve called the millennial generation smaller than the baby boomer generation. Other research shows just the opposite.

There are more millennials because they started from higher birth levels than the baby boomers. But the slope of the wave of baby boomers from 1936 to 1961 is like a huge 10-foot wave. The millennials will never have that growth rate even at their full peak spending period. They won’t take us to new heights. So the economy basically goes sideways as far as the eye can see. Demographics are going to be shrinking, even in the next boom.

In your book, you call President Trump “Mad Max” and “a national security risk” because of “his flapping lips…” Your late father Harry S. Dent. Sr. was a strategy advisor to three presidents, including Richard Nixon, in whose administration he worked after his election. What do you think your father would say about Donald Trump?

He’d say that Trump had a brilliant strategy for getting elected because he used to tell me that it’s not the middle class that decides elections — it’s the All Star Wrestling fans, the 15% to 20% clueless, bigoted, narrow-minded, dumbest people in the country, who are easily influenced. Those are the people who have been most pissed off in recent decades because their wages and earning power have been falling as a result of foreign and immigrant workers. Trump [targeted] them squarely and won them by [a margin of] about 80%.

— Related on ThinkAdvisor: