At every turn, pundits and political scientists underestimated Donald Trump. When he announced he was running to be president of the United States, they laughed. When he led the polls for the GOP nomination, they predicted his popularity would be short-lived. When he became the Republican nominee, they celebrated. Against a Rubio or even a Christie, Clinton might have lost. But against Trump?

We’ve underestimated Trump over and over and over again. And over and over and over again, we’ve all paid a heavy price. And yet, many of the same pundits and political scientists who confidently predicted that Trump would never be president are now confidently predicting that his presidency will soon be tanked by incompetence and unpopularity.

According to a former spokesman for the Clinton campaign, Democrats will find it easy to stand up to Donald Trump: The “lack of support” for the president-elect, she argues, is so extreme that “his coattails look a little more like a T-shirt.” Bill Gross, a famous fund manager on Wall Street, anticipates that Trump’s tenure in the White House will be “a short four years.” Even Michael Moore, who was more concerned about a potential Trump victory than most throughout the campaign, has now turned into something of an optimist—predicting that Trump will not even be able to serve four full years. If you want to bet on Donald Trump getting impeached these days, you’ll only win $1 for every $1 you wager.

It is perfectly possible that the dim view of Trump’s ability to execute his vision will prove correct. But before we default to the kind of assumption that has led us astray before—the confident belief that the past is a reliable guide to the future; that most things will keep on going as they always have; that stasis is sure to win out in the end—we’d better take a moment to check our optimism.

What are the main grounds that supposedly prove that Trump will fail to transform the country? And just how reassuring are they?

Trump’s approval ratings are terrible.

Every time I look at Twitter or Facebook, I see another poll showing dismal ratings for Trump. Until a few days ago, it had me convinced that, as Josh Marshall put it, “Trump, his agenda and his party are deeply unpopular. Indeed, Trump’s gotten steadily more unpopular over the last four weeks.” Then I went to check the figures out for myself.

The polls that get most traction on social media, it turns out, are those that make people like you and me feel better. But for every poll showing Trump with a net favorability rating of -21, there has also been one showing him at +7. On average, 43.5 percent of the population now sees him favorably and 48 percent unfavorably.

That’s not exactly good: Trump’s approval ratings really are worse than those of any other president-elect in recent history. But nor is it nearly as terrible as most of my Facebook friends seem to assume: Trump’s ratings have been steadily improving since the election and are now at a record high for him. If he keeps defying his low expectations, he may end up surprisingly popular.

Scandal and incompetence will bring Trump down.

Over the last eight days, there have been more scandals involving Donald Trump and his wider team than Barack Obama’s administration has had to weather over the course of eight years.

There was the revelation that Russia may have material to blackmail Trump. There was the revelation that Trump would not place his vast business holdings in a blind trust. There was the revelation that one of his nominees had plagiarized parts of her dissertation. These scandals showcase a level of sleaze and corruption that may hurt Trump in the estimation of voters. As important, they suggest a level of incompetence that may well dog his ability to effect real change once he gets into office. Getting things done in government is far from easy—and with a team of amateurs, so the hope goes, Trump’s bluster will be no match for the vast machinery of the federal bureaucracy. As one fairly typical op-ed, invoking a famous quote about Dwight Eisenhower, puts it: “He’ll sit here, and he’ll say: ‘Do this! Do that! And nothing will happen.’ ”

There’s something to this hope. Trump will likely do less damage than he might have done if he had a highly professional, ideologically coherent set of fellow travelers at the ready. And there is a decent chance that some big scandal that hurts voters in a direct way—something of the magnitude of the botched federal response to Hurricane Katrina—will come to define Trump in the eyes of the electorate.

But this scenario is not as reassuring as it looks. Getting things done in government is very hard, but destroying things in government is pretty easy. It doesn’t take incredible skill for the president to command government scientists to cease doing climate-related research, to rescind executive orders protecting the dreamers, or to abolish the United States Agency for International Development. And even some affirmative steps can easily be taken by a cadre of incompetents: A policy of mass deportations, for example, may be less systematic when run by amateurs, but it’s unlikely to be less cruel.

Similarly, in a highly partisan environment, sleaze and scandal are less poisonous than they might be in normal times. And since Trump doesn’t claim the moral high ground—openly boasting that he is a smart self-dealer—he rather enjoys the sound of his opponents clutching their pearls. “Like me,” he will say, “they are in it for themselves. Unlike them,” he will add with one of those toe-curling smirks, “I’m upfront about it.”

His supporters will rebel once he slashes taxes on the rich.

Trump campaigned as a friend of ordinary working people. But his actual policy proposals would slash taxes on the rich and hand millions to big corporations. As Matt Yglesias writes, he “is proposing to bring back the exact policy mix of tax cuts for millionaires and deregulation for banks and fossil fuel extractors that brought the global economy to its knees under George W. Bush.” This, the suggestion goes, presents a deep strategic problem for Trump: If many ordinary Americans suffer from his policies and a large number of voters blame him for their misery, he would be in big trouble.

But that is far from assured. While tax cuts for corporations and the rich are disastrous in the long run, his policies might well stimulate a boom in the short run. If he gets the timing right, he can run on a platform of success in 2020.

Just as important, voters are terrible at judging what presidents are actually responsible for. By saving a few hundred jobs here and there—and keeping the media focused on his showmanship—he can play the part of a hero even as he’s tanking the economy. So far, this strategy has worked astoundingly well, with major networks breathlessly reporting on the jobs he has supposedly saved.

He can’t build the wall.

If there’s one article of blind faith among Trump’s opponents, it’s that he can’t deliver on his promise to build a wall between the U.S. and Mexico. It would be too expensive, they say. In any case, they add, the terrain on some parts of the border does not lend itself to a brick-and-mortar wall.

But this just sets Trump up for another very easy win. Yes, it would be difficult to build a literal wall on some parts of the border. But it’s ridiculous to imagine that Trump’s supporters will think he betrayed them if stretches of the Mexican border are secured by wire fencing or by natural obstacles. Yes, the wall will prove more expensive than he’s admitted. But voters for whom immigration is a top concern would happily spend billions of dollars on the wall—and the idea that, given the necessary funds, today’s United States would somehow prove unable to do what China accomplished thousands of years ago is, frankly, bizarre.

Will every part of the U.S.-Mexican border be covered by a high brick wall? No. Will Trump be able to take a grand victory tour in front of something that looks pleasingly like a wall when he campaigns for reelection? Yes.

The constitution will stop Trump from abusing his powers.

Trump is likely to do a lot of bad things: Deport millions of people. Wreck the economy. Pull out of the Paris climate accord. But perhaps my biggest worry is about the effect he might have on the system itself: Time and again, he has broken the most basic norms of democratic politics. And time and again, he has threatened to overstep the bounds of his constitutional authority. If he does half of what he said he would, he will do permanent damage to American democracy—and by extension, to democracy across the globe.

And yet, many pundits and scholars are deeply skeptical of this scenario. The checks and balances built into the Constitution, they say, make it very difficult for Trump to abuse his powers in a blatant way. I’m not convinced. All through its history, America enjoyed two big advantages: well-designed institutions and a deep commitment to democratic norms. That commitment is now weaker than it has ever been. What will be the consequences?

Since we’ve never had a president with so little interest in democratic values or a population that has accepted such extreme behavior on the part of its leader, we can’t quite know. But the evidence from other countries is hardly reassuring: The problem with failed democracies from Russia to Thailand is not that their institutions were terribly designed; it’s that their countries did not have enough of a commitment to democratic values to make those institutions work.

Neither Congress nor the Supreme Court, as constitutional lawyers are wont to point out, has any battalions at its disposal. To stop the commander-in-chief from abusing his powers, a huge majority of the population has to turn against him, and a principled legislature has to stand up to executive overreach and the violation of democratic norms. But Trump was elected president despite breaking every norm in the book; has gotten more popular even as he’s praised a foreign dictator and trashed his own security apparatus; and has met surprisingly little resistance among congressional Republicans to whom repealing Obamacare seems to be more important than standing up for the Constitution.

Though he often sounds upbeat, Barack Obama grasps this point very well. “Our Constitution is a remarkable, beautiful gift,” he said in his farewell speech on Tuesday. “But it’s really just a piece of parchment. It has no power on its own. We, the people, give it power. We, the people, give it meaning — with our participation and with the choices that we make and the alliances that we forge.”

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Over the course of the campaign, we should have learned just how easy it is to fall prey to wishful thinking. And yet, many of us are at it again. With a preternatural confidence oddly unshaken by the last months, pundits once again claim that Trump is sure to fail. But the reasons they give for their optimism are, as ever, weaker than they first appear.

That Trump isn’t sure to fail does not mean that he’s certain to succeed. It’s perfectly possible that he’ll crash and burn. But to figure out how to beat Trump, we must start by taking him—and the danger he poses—seriously.