CONVENTIONAL wisdom gets turned on its head quickly in the financial markets. Although many on Wall Street were gloomy about the prospects under a Trump presidency, the markets have performed a sharp U-turn after the overnight decline on election day. So many people (including The Economist) had warned of the crazy policies of Donald Trump that there was always going to be a market for contrarians to say that he won’t be that bad after all. Especially among white, prosperous financial commentators there is a willingness to “normalise” Mr Trump—to tell the groups he has insulted and threatened to get over their fears. What Mr Trump does in office will be different from what he said on the campaign, they think. (If you want to see what minority groups have to put up with from Mr Trump’s supporters, look here.)

What investors clearly hope is that Mr Trump will get to implement some of his policies but not all—in particular the tax cuts for the wealthy and for business, increased military spending and financial deregulation. An early sign that this may not be that “revolt against the elite” that some commentators are claiming is a surge in bank shares. There was even a jump in the shares of Goldman Sachs, whose CEO Lloyd Blankfein featured into the last anti-semitic ad of the Trump campaign (in a section muttering darkly of “global special interests”, it featured photos of Janet Yellen, George Soros and Blankfein).

By contrast, markets are betting that the nativist elements of the Trump agenda—trade protection and a willingness to anatagonise America’s traditonal allies and cozy up to Russia—will be dropped. The result will be an economic boom as a fiscal stimulus works its way through the economy.

If this platform seems familiar, that is because it is. Tax cuts and financial deregulation were all part of the programme of George W. Bush. Look how that ended—in the financial crisis of 2007 and 2008. Wall Street is counting on the fact that Mr Trump will be Bush 3.0—that voters in the rust belt have been tricked through some patriotic tub-thumping and attacks on political correctness into voting for a traditional Republican. Quite how voters will react to being “fooled again” (remember the great Who song) will be interesting to see. (Ironically ex-President Bush refused to vote for Trump.)

Funnily enough, the one good reason I can think of voting for Mr Trump is that he might be able to get a bit of extra infrastructure spending through Congress (having driven on California’s highways recently, they are an insult to one of the richest parts of the world). But the Trump rationalisers are also guilty of staggering naivety. Here is Mickey Levy of Berenberg Bank:

Now that Trump is president-elect, his posture will be much more diplomatic. His public speeches will be closely managed. He will be less prone to erratic and off-the-cuff remarks. Every president-elect assumes the role of president and starts to behave presidential.

This reminds me of people who marry a spouse with a doubtful temperament on the grounds that he or she will change after the wedding. Good luck with that, as they say. This is a 70-year-old man who has spent his life running companies where he is the boss and is used to getting what he wants. He is not going to change. Anyone who thinks he will should read this New Yorkerpiece about the ghostwriter who prepared “The Art of the Deal”, Mr Trump’s bestseller. That writer finds it impossible to believe that Mr Trump will be able to focus on policy detail:

“Trump has been written about a thousand ways from Sunday, but this fundamental aspect of who he is doesn’t seem to be fully understood,” Schwartz told me. “It’s implicit in a lot of what people write, but it’s never explicit—or, at least, I haven’t seen it. And that is that it’s impossible to keep him focused on any topic, other than his own self-aggrandisement, for more than a few minutes, and even then…” Schwartz trailed off, shaking his head in amazement. He regards Trump’s inability to concentrate as alarming in a presidential candidate. “If he had to be briefed on a crisis in the Situation Room, it’s impossible to imagine him paying attention over a long period of time,” he said.

There are two big risks here. The first is that, given his traditional Republican agenda, Mr Trump will feel the need to throw some “red meat” to his base with aggressive actions on trade or foreign policy; in these areas his actions are much less constrained by Congress (it has to approve treaties but can’t stop the president breaking treaties). The second is that his temperament is tested fairly quickly. It is all very well to be magnanimous in an acceptance speech; the real test of character comes in the face of setbacks or determined opposition. Imagine that, in the face of a highly stimulatory fiscal policy, the Federal Reserve starts to tighten aggressively. Apart from attacking her in campaign ads, Mr Trump has already said that Ms Yellen “should be ashamed of herself” and implied that the Fed was keeping policy loose to get the Democrats re-elected. Will he respect the independence of the central banks, or indeed the courts?

All this may explain why the Treasury bond yield is up to 2.07%, having leaped a third of a point since the initial flight to safety on Tuesday night. Bond investors understand the risks. And frankly if you don’t understand the risks involved in appointing a short-tempered narcissist with no experience as the leader of the free world, you’re not paying attention.