As these examples make clear, this clause in the Constitution is hardly an anachronism. We are in danger of having a president who could violate it if he does not disentangle his business operations from foreign governments. The potential violations also include the benefits conferred on Trump in connection with outstanding loans from the Bank of China, which is controlled by the Chinese government, as well as any investment or involvement of sovereign wealth funds in his many projects around the globe, and foreign governments putting up their officials or diplomats at Trump hotels or even those governments buying apartments in his buildings—at times likely vying for the most expensive suites. All of this will become unconstitutional come January 20.

Nor is Trump's Twitter announcement last week that he will completely exit his "business operations" enough. Although it is of course important that he have no involvement in Trump business operations, in order to avoid the constitutional conflicts, he must also exit the ownership of his businesses through using a blind trust or some other equally effective disposition. Otherwise he will have a personal financial interest in the foreign government payments and benefits that flow to his businesses daily.

The only workable solution to this problem (and Trump’s many other conflicts) is for him to do what ethics lawyers have been urging him to do for months, which is to divest himself of his business holdings before he becomes president. Alternatively, the Constitution allows Congress to approve Trump's receipt of this vast global flow of foreign government cash and other benefits to him. Congressional deliberation and oversight would confer the benefit of hearings and of offering some of the transparency about Mr. Trump's holdings that have so far been denied to the public by his refusal to release his taxes. But we doubt that would be a politically attractive alternative to his fellow Republicans, and he probably could not count on support from the minority party. Accordingly, divestment and a blind trust is the way to go, and indeed, our proposal has been endorsed by an array of conservative voices sympathetic to Trump, including the Wall Street Journal, the New York Post, Peggy Noonan, and Peter Schweitzer, the author of Clinton Cash.

And what if Trump declines, as he has so far, to eliminate his foreign government emoluments that violate the Constitution? That brings us back to the Electoral College. Each elector should, as two have now done, review the Constitution and the facts, and his or her legal and moral obligations. Twenty-nine states and the District of Columbia require electors to vote consistent with the popular vote of his or her state; the others allow them to vote their conscience, as the Framers intended. Even in those states that bind electors, the constitutionality of the limits is unclear and penalties are generally light. Short of that, electors can move now to demand, individually or collectively, more information to inform their choice. And electors also have the option of raising these issues with the courts for guidance, for example through seeking a declaratory judgment that they need not cast their ballot as required by state law if doing so would elect a president who could violate the Constitution on his first day in office.