Students of James Buchanan, co-founder of the public-choice school of economics, must puzzle over the furor caused by Donald Trump’s conflicts of interests. All presidents act out of self-interest, all the time; any relation to the public interest (whatever that is) is, at best, incidental. Politicians are always pursuing their own advantage as they see it. Buchanan taught us not to think of government officials behaving in accordance with some platonic ideal of the public good. They react to pressures and incentives just like everybody else. When President Obama withdrew U.S. troops from Iraq and “ended the war” (some would say he ended the peace), was he acting from national interest or political self-interest? When Mr. Obama falters on helping poor children escape from bad schools because he needs the favor of teachers unions, is he acting from self-interest or the public interest? By definition, everything a president does is, to his critics, bad public policy. If Mr. Trump had no business interests, his opponents would still see his policies as self-interested attempts to curry favor with some particular voting bloc, donor group, logrolling legislation faction, future benefactors of his presidential library, or journalists and biographers whom he hopes will pen glowing tributes. In what sense, then, are his business conflicts a meaningful complication of the necessary suspicion that follows all presidential actions? Mr. Trump, with his forthcoming Dec. 15 press conference, promises a “solution.” Reason tells us any solution can only be ceremonial. If he transfers control to his children, he will still own a big stake in the Trump business. If he sells out to his children entirely, he will still care about their future success. If he dismantles the business, disinherits his children and retires the Trump brand (which he would never do, since the cost would be extravagant), he would still wake up to find his every action assailed by opponents. Buchanan, who won the Nobel Prize in 1986 and died in 2013, might say our idea that politics can be cured of conflicts of interest is misguided. He advised “politics without romance.” On the flip side, at least the press and political opposition will find it easy to police Mr. Trump’s business conflicts compared with many other conflicts that presidents are heir to. If he sells out the U.S. national interest in dealings with the Philippines because his name embellishes a Trump Tower in Manila, the media and critics both Democratic and Republican will not fail to notice and turn the fact to his disadvantage. The press might also have to admit that, in many cases, what’s good for America is good for the Trump Organization-an alignment of incentives. It does not follow that because a policy would cut his company’s taxes or relieve it of costly regulation, it’s bad public policy. Mr. Trump’s appeal to voters was partly based on making life easier for business investors in America. What about the Constitution’s emoluments clause? The words “blind trust” are not mentioned, and established practice has certainly permitted presidents to own stakes in companies that do business abroad. Let’s grow up. In our democratic and interest group-mediated political system, the public expects politicians to be self-interested. The public also hopes and trusts, because political actions will be subjected to withering observation and criticism, that the net result will tend toward the public good. The public’s deepest interest is that the recursive game keeps going. There’s another election coming, another legislative vote, a new interest group or voting bloc making its voice felt. There is always a chance for course correction. As politicians navigate these decision points in their own interest, we hope society is kept on track to a semblance of peace, prosperity and social order. For some noisemakers, that President Trump would greedily misuse his office is a sincere fear. Many others, let’s face it, intend to oppose his policies from the get-go. These critics are only too delighted at the prospect of being able to use his business interests to discredit him. The Trump Organization is their godsend. Their demands for Mr. Trump to liquidate his holdings are insincere, since their plan is to spend the next four years deriding and delegitimizing anything Mr. Trump does in the way of tax-cutting or deregulation as nothing but corrupt attempts to enrich himself. Donald Trump, with his Twitter habits, with his detachment from party, is a new kettle of fish. Many of the beholders now shrieking like schoolchildren are simply outraged at the unfamiliar. Here’s a modest suggestion: Why not widen our tolerance a bit? Why not allow that Americans have the right to pick a business owner as president? Let’s see how their choice plays out.