NEW YORK (Project Syndicate) — Never in recent history has a change of leadership attracted as much attention and speculation as Donald Trump’s rise to the U.S. presidency. What this change signifies and what it portends requires unraveling three mysteries, because there are three versions of Trump.

The first Trump is the friend of Russian President Vladimir Putin. Trump’s enthusiasm for Putin is the most consistent part of his rhetoric. Despite a worldview that regards the United States as a victim of foreign powers — China, Mexico, Iran, the European Union — Trump’s ardor for Putin burns bright.

Depending on who is opining, Trump is either a naive admirer of strongmen like Putin or a long-time tool of Russian intelligence. There is almost surely a backstory here, one that could destroy Trump’s administration if some of the lurid rumors are confirmed. We now know that some key dates and details in the infamous “dossier” on Trump’s relations with Putin, assembled by a former British intelligence officer, have been verified.

A growing body of circumstantial evidence suggests that Trump has been backed by Russian money for decades. Russian oligarchs may have saved Trump from personal bankruptcy, and one reportedly traveled to a number of Trump’s campaign stops, perhaps acting as a go-between with the Kremlin. And many top members of Trump’s team — including his first campaign manager, Paul Manafort; ousted National Security Adviser Michael Flynn; former Exxon Mobil XOM, +4.24% CEO and now Secretary of State Rex Tillerson; and hedge-fund magnate and Commerce Secretary Wilbur Ross; all have significant business dealings with Russia or Russian oligarchs.

The second version of Trump is a greedy businessman. Trump seems intent on transforming the presidency into another source of personal wealth. For most people, the presidency would seem to be its own reward, without cashing in (at least not while in office). Not for Trump. Contrary to all previous norms, and in violation of the standards set by the Office of Government Ethics, Trump is keeping his business empire, while family members maneuver to monetize the Trump name in new investments around the world.

The third Trump is a populist and demagogue. Trump is a non-stop font of lies, who brushes aside the inevitable corrections by the media with the charge of “fake news.” For the first time in modern American history, the president is aggressively demonizing the press. This past week, the White House barred the New York Times, CNN, Politico, and the Los Angeles Times from a news briefing by the press secretary.

On some interpretations, Trump’s demagogy is in the service of his chief strategist, Stephen Bannon, who defends a dark vision of a coming war of civilizations. By raising fear to the highest possible level, Trump aims to create a violent America-first nationalism. Hermann Göring chillingly explained the formula from his Nuremberg jail cell after World War II: “[T]he people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country.”

Another theory is that all three Trumps — friend of Putin, wealth maximizer, and demagogue — are really one: Trump the businessman has long been supported by the Russians, who have used him for years as a front for laundered money. One might say they won the jackpot, parlaying a small bet — on manipulating the outcome of an election they most likely never expected him to win — into a huge payoff. On this interpretation, Trump’s attacks on the press, the intelligence agencies, and the FBI specifically aim to discredit these organizations in advance of further revelations regarding the Trump-Russia dealings.

Those of us who lived through Watergate remember how difficult it was to hold Richard Nixon to account. Without the revelation of secret White House tapes, Nixon almost surely would have escaped impeachment and served out his term. The same was true with Flynn, who lied time and again to the public, and to Vice President Michael Pence, about his communications with the Russian ambassador before he assumed his post. Yet, like Nixon, he was tripped up only because his lies were recorded, in this case by the U.S. intelligence agencies.

When Flynn’s lies were exposed, Trump’s reaction, characteristically, was to attack the leak, not the lies. The main lesson of Washington, and indeed of strongman politics in general, is that lying is the first, not last, resort.

If Congress has enough honest members, a majority, knowing that Republicans will not police Republicans, will demand an independent investigation of Trump’s Russia ties. Republican Sen. Rand Paul was explicit on this point, declaring that it “makes no sense” for Republicans to investigate Republicans. Trump seems intent on turning up the pressure on the FBI, the intelligence agencies, the courts, and the media to back off.

Demagogues survive because of public support, which they try to maintain through appeals to greed, nationalism, patriotism, racism, and fear. They shower their supporters with short-lived cash, in the form of tax cuts and income transfers, paid for by running up the public debt and leaving the bill to future generations. Trump has so far kept America’s plutocrats happy, through promises of unaffordable tax cuts, while mesmerizing his white working-class followers with executive orders to deport illegal immigrants and bar arrivals from Muslim-majority countries.

None of this has made Trump very popular. His approval ratings are historically low for a new president, around 40%, with roughly 55% of respondents disapproving. Judicial challenges to executive actions, fights with the media, tensions stemming from rising budget deficits, and new revelations regarding Trump and Russia, will keep the pot boiling — and Trump’s public support could evaporate.

In that case, Republican leaders are more likely to turn on Trump. But no one should ever underestimate a demagogue’s willingness to use fear and violence, even war, to maintain power. And if Putin is indeed his backer and partner, Trump’s temptations will be strong.

Jeffrey D. Sachs, professor of sustainable development and professor of health policy and management at Columbia University, is director of Columbia’s Center for Sustainable Development and the U.N. Sustainable Development Solutions Network.

This article was published with the permission of Project Syndicate.