[Inspired by similar comments from both Nassim Taleb and Peter Schiff, here and here.]
During the campaign, Trump said that the stock market was in a big fat bubble, and that if he won, the Fed would wait to raise interest rates until he took office, so that the bubble bursting would not be blamed on Obama but on Trump. He never was a stock market guy, keeping his company from becoming publicly traded, and never basing his wealth on stocks.
Eager to point to good news during his tenure so far, especially on economic indicators, he has hyped the rise of the stock market since his election. His surrogates such as Kellyanne Conway do likewise on the media, hyping the trillions of dollars of wealth added thus far.
But this is just the bubble continuing to inflate, and none of that added wealth is real. When it pops, Trump ought to have distanced himself as much as possible from the stock market -- otherwise he will be blamed for "crashing the markets" or "blowing up the economy" or something else that frames wealthy stock-owners as the only class worth caring about, rather than the workers who put Trump over the top in the Rust Belt.
Working-class and middle-class people have been doing worse for 30-40 years straight, whether the stock market has been bulls or bears. The overall trend in stocks has been only upward over this time, though, meaning that if anything the stock market must crash and stay cut down to size if the working and middle classes are to recover the standard of living they used to enjoy before the yuppies took over during the 1980s.
Trump and his team must remember that Wall Street does not form any part of their base -- it is the main power group within the Democrats, not the Republicans (whose main power group is the Pentagon). He owes no part whatsoever of his victory to Wall Street, so he is in a position to tell them to go eat shit, and to put the blame for a declining Dow squarely where it belongs -- on the Wall Street party, the Democrats, for inflating the bubble during Obama's entire eight years. 
The Fed is already starting to raise interest rates, making debt more expensive to pay back, and with the gigantic amount of debt out there, pretty soon the rate hikes are going to set off a pretty big drop. So it's just like Trump said about the Fed waiting until the Democrat was out of office, and a Republican could be blamed.
Looking over a list of recessions since WWII, it looks like they're more likely to hit under Republican Presidents. I wonder if the Democrats being the finance-friendly party goes back that far, and they've been setting up their Republican successors each time to take the fall.
Aside from sabotage by the opposition party, there's also the massive re-allocation of federal funds that the Republicans will undertake when they gain power -- away from finance and toward the military. There's only so much gravy to go around, so perhaps gorging the military is enough to starve the banks. Republicans deliver military bubbles rather than financial bubbles, and when the Democrats replace them, the military bubble pops and turns back into a financial one.
At least that's the pattern since Reagan, when the GOP became the militarist party (it was the Democrats who began and escalated Vietnam, and Nixon who ran on getting us out), and when it makes sense to talk about a "Wall Street party" inflating a stock market bubble. There was the double-dip recession of the early '80s, the isolated Black Monday of '87, and the early '90s recession, all under Reagan-Bush. Then silence under Clinton, while the tech / dot-com bubble inflates like crazy. That bubble pops under Bush Jr, and later so does the housing bubble. Then silence under Obama, while a new bubble inflates, still related to tech and internet companies. That's bound to get wiped out during the Trump administration -- and perhaps be followed by a second crash later into the eight-year term.
To prepare for what seems to be a certainty, with only the timing and severity unknown, Trump must not only distance himself from the bubble, but loudly and repeatedly put the blame onto the Democrats, who are controlled by Wall Street and do the bidding of the big banks. He's already made us familiar with the line "I inherited a big fat mess," so might as well stick with that one.
And he must also make clear that, unlike the typical Republican, he was elected thanks to working-class voters, and he is only going to pay attention to measures of their economic health when he judges the success or failure of his policies. They do not own any stock, and the stocks only soar in value when the companies slash costs by firing American workers (off-shoring and bringing in immigrant workers). So if the stock market crashes, it will be due to the phony bubble wealth evaporating, plus the companies having to hire American workers and pay them a decent income again.
I know Trump wants to please the business community, but not if it means continuing to inflate their bubble and continuing to peddle the view that the stock market is an index of the average American's economic well-being. He can tell them that the stock market declining will return big businesses to a more sound and robust state, and not soft and flabby from the government feeding them everything.
Might as well go straight to the American people by using Twitter, once the market crashes: "Wealth lost by 1% who own stocks = $10 trillion. Wealth lost by workers who own none = 0. Inequality narrowing -- nice!"
 He is beholden to the Pentagon, and cannot get his intended policy of "getting along with Russia" and letting Assad stay in power. Obama, in contrast, did not owe anything to the Pentagon, so he was more free to attempt a "Russian re-set," and stalled long enough on striking Syria and put it up to public debate, to the point where he could wiggle out of doing the Pentagon's bidding. But Obama was beholden to Wall Street, and had to go along with whatever they wanted, i.e. bailouts for year after year.
Even if Bernie had won, he would have found himself in the same position regarding bailouts that Trump is in regarding militarism -- campaigning against it, but forced into it by the main power group that controls his party.