Unless Congress acts swiftly to force Donald Trump to divest his businesses, the only thing standing in the way of what could be the most corrupt governmentin our history is his word.

None of us quite know how wealthy Trump really is, but there is little disagreement about what his word is worth: Nothing. That’s not just my opinion. About two-thirds of Americans say they don’t think he’s trustworthy.

And for good reason. Trump has never felt bound by the ethics and norms of behavior that most other businessmen take for granted. Thanks to great reporting byDavid Cay Johnson, Timothy O’Brien, Susanne Craig, Marc Fisher, Michael Kranish, David Fahrenthold and dozens of others, we know what kind of businessman he’s been.

His business dealings may have been (mostly) legal, but he’s always crossed ethical boundaries to line his own pockets. He has refused to pay his workers. He has hired undocumented workers. He has refused to pay small businesses that did work for him. He has defrauded his customers. He has cozied up to the mob. He’s bragged about bribing politicians. He has no qualms about borrowing money that he will refuse to repay. He’s been sued countless times by the people he’s stiffed. He files frivolous lawsuits against anyone who asks for what’s rightfully theirs. On Friday, he reached a $25 million settlement to resolve allegations of fraud at now-defunct Trump University. He used his charitable foundation for his own ends. He even used his presidential campaign to benefit his companies, and reports suggest that he’s already mixing his two roles of president and businessman.

Currently, there is no law that would prevent Trump from using the Oval Office to enrich himself and his family. The ethics laws that most government officials must obey, which require divestiture of any assets that could create a potential conflict of interest, don’t apply to the president, the vice president or members of Congress.

That must change now.

Former ethics officials in the White House and a dozen good-government organizations are demanding that Trump divest his business holdings. Every American — regardless of their political party or of how they voted two weeks ago — should demand the same.

In the past, presidential conflicts haven’t been a problem. Ever since Watergate, presidents have voluntarily placed their wealth into blind trusts or have put their money into plain-vanilla investments such as cash, bonds and mutual funds to reassure the public that the actions they take as president aren’t self-aggrandizing.

But Trump has refused to do what other presidents have done — erect a big, beautiful wall between his own finances and his sacred oath to promote the general welfare of the nation. Instead, he’s giving control of his companies to his children and his son-in-law, Jared Kushner, the very same people who are advising him as he plans his transition into the White House.

Kushner and Ivanka Trump even attended a meeting between Trump and Japanese Prime Minister Shinzo Abe, a clear sign they’ll be mixing private and public business.

Trump’s “blind trust” is not blind because he and his family know exactly what he owns. And it’s not a trust because the people who will handle his finances are not independent. They will be privy to every state secret, and will know exactly how to use that knowledge to make more money. They’ll know what policies to adopt that will favor Trump’s businesses and put his competitors at a disadvantage. As president, Trump will appoint the officials at every regulatory agency, will be the boss of every government bureaucrat, and will be able to select judges who have lifetime appointments.

Worse yet, Trump’s businesses are so complex and so opaque that no one outside the Trump Organization knows precisely what they do. Could Trump be partners with the Chinese or Russians or North Koreans or the mafia or ISIS? No one knows. We do know that any payment by a foreign government to the Trump Organization — perhaps even for foreign diplomats to stay at the Trump International Hotel in Washington — would violate the U.S. Constitution.

Congress must build an impregnable wall between the Oval Office and the Trump Organization. Congress must pass a law quickly requiring that Trump and all future presidents and vice presidents sell all of their holdings and place the money in a blind trust upon taking office. (Of course, the law should apply to members of Congress as well if we really cared about draining the swamp.) Trump and his family must not know the details of the blind trust that would manage his wealth. The people managing that wealth must have no connection with Trump or his family.

I know any appeal to the Republican-controlled Congress to rein in Trump seems naive at best. Why would Republicans vote against Trump on any issue?

Because no one voted to make Trump a rich(er) man. Because many Republican lawmakers have already expressed deep doubts about Trump’s character. If you want Trump’s presidency to be a success for the Republican Party and what it stands for, the last thing you’d want is for Trump to be distracted by his business interests. If Trump doesn’t divest, every act he takes would spark accusations that he’s doing it for the Trump brand, not for the people.

The votes are there to compel Trump to divest, but only if the people force the Congress to vote. There’s really no reason why this law shouldn’t pass unanimously.

By running for president, by promising to “drain the swamp” of corruption, by pledging “America First,” Trump has implicitly agreed that America’s interests should come before his own. No governmental official should ever have to choose between what’s right for the people and what’s right for their own bottom line. If the Trump Organization survives, he’ll have divided loyalties.

Trump really can’t have it both ways, because at some point (probably at least once a day) a conflict will arise between his oath of office and his responsibility to his businesses and his family’s wealth. Trump will have to decide whether he will put America First, or the Trump family first. Nothing in his character or his history suggests he’ll make the right choice.

Even a saint would be tempted to make the wrong choice, and Trump is no saint.

Build the wall, and drain the swamp.