Donald Trump managed to keep making money and building his business while he campaigned for president, and he’s making money off his transition. He appears likely to keep making money and building his business after he’s inaugurated. You have a problem with that?

Trump promised to “self-fund” his presidential campaign, and he did, for awhile at least. Even then, he managed to pay much of the money to himself. The Trump campaign rented space in Trump Tower, hosted events at Trump resorts, bought food from Trump restaurants and paid Trump’s airline company for the use of Trump’s plane.

In June, Trump began turning to donors to fund his campaign, but the money kept flowing to Trump enterprises. Trump even jacked up the rent in Trump Tower. All of this is legal, by the way, even required, since giving freebies to his campaign would constitute an illegal in-kind contribution.

From the moment he descended on a gold-plated escalator to announce his candidacy, Trump used his properties as backdrops for his campaign. The campaign bought $55,000 worth of his books. Ivanka sold the dresses and jewelry she wore at campaign appearances. Then there are the hats, emblazoned with “Make America Great Again,” the slogan Trump copyrighted in 2012. Never has product placement been so central to a political campaign.

Trump took time away from his campaign in June to promote one of his golf resorts in Scotland. In October, he commandeered a day of campaign coverage to pump up the opening of his newest hotel, in the old Post Office building on Pennsylvania Avenue in Washington, DC., a building the Trump Organization leases from the federal government.

Trump is now cashing in on the transition, with the taxpayers picking up more of the tab. The Secret Service has paid millions for travel on Trump’s plane and the use of his properties. Congress has appropriated $7 million to pay for office rent and other transition expenses. While picking his cabinet, he has drawn the spotlight to Trump properties in Manhattan, New Jersey and Florida.

Don’t expect anything different once President-elect Trump becomes President Trump. In Trump’s new hotel, a short walk from the White House, the top suite goes for $19,000 a night, and you can expect it will be heavily booked by people hoping to get on the good side of the new president — whether or not Trump carries through on his promise to put his company in the hands of his children

Trump has conventional conflicts of interest — he holds stock in the company building the hotly disputed Dakota Access Pipeline, for instance. But Trump has said, correctly, that the president is exempt from federal conflict-of-interest laws.

The problem comes from Trump’s many foreign investments, and the Constitution’s little-explored “emoluments clause,” which prohibits federal officials from accepting gifts of value — “emoluments” — from foreign governments or state-owned enterprises unless approved by Congress. If a foreign government or entity rents a suite in the new hotel, which seems likely, is that a constitutionally prohibited emolument? What about the Bank of China, which already rents space in Trump Tower?

The more serious problem isn’t that Trump will profit from his presidency. He wouldn’t be the first president to walk out of the White House wealthier than when he moved in. The problem comes when foreign governments get involved.

Trump’s not big on diplomatic niceties, and he doesn’t consult with the State Department before opening his mouth. Last week he met with Nigel Farage, a leader of Britain’s Brexit movement. Sources in the meeting said Trump urged Farage to oppose the expansion of offshore wind farms like one proposed off the coast of Scotland, which he has long argued would spoil the view from one of his golf resorts. Then Trump tweeted that Farage would make a great ambassador from Britain to the U.S.

Where to start? Does Trump not know that it is up to the foreign government to name its ambassadors, not the leader of the receiving state? Does he know there is already a British ambassador to the U.S., who might take offense at the tweet? It’s bad enough for a U.S. president to stick his finger into a policy decision made by a foreign government. It is immeasurably worse for a president to interfere in order to boost the value of his own private investment.

So consider a plausible scenario: Six months into his first year in office, the Trump administration is involved in difficult negotiations with the British government over, say, contributions to the NATO budget. Suddenly the British Home Secretary announces that the proposed wind farm within view of Trump’s resort has been killed. Is there a quid pro quo? Hard to say. Has the “emoluments clause” been violated? If so, who can prosecute it?

Other scenarios could be more serious. The Trump Organization’s real estate portfolio includes properties in India, Turkey, Dubai, South Korea, Panama, Canada and the Philippines. Many aren’t owned by Trump, but pay him to use his name, which is itself controversial. The president of Turkey has already demanded Trump’s name be removed from Trump Towers Istanbul. Any of those properties could be a target for terrorists or a pawn in a diplomatic standoff.

If a foreign power tests the new president, can we count on Trump to keep the national interest separate from the interests of the Trump Organization? Maybe, but it hasn’t happened in his campaign or in his transition. Moreover, I can’t recall a single instance in Trump’s life where he has sacrificed personal gain for the public good.

So far, we’ve seen no indication that Trump takes these problems seriously, but he should. Washington loves scandals so much it spent the Clinton and Obama administrations making them up out of next-to-nothing. Unless he builds a convincing firewall, Trump’s business entanglements will provide plenty of raw material for the scandal machine.

— Rick Holmes writes for GateHouse Media and the MetroWest. He can be reached at rholmes@wickedlocal.com. Like him on Facebook at Holmes & Co, and follow him @HolmesAndCo.