PRESIDENT-ELECT Donald Trump is right to close down the Donald J. Trump Foundation, a charitable organization that been dogged by questions about its practices. Mr. Trump must not interfere with the ongoing investigation by the New York attorney general, but he should shutter the foundation as quickly as possible so it will not become a tempting channel for influence seekers. Meanwhile, Mr. Trump should take a similarly clear-minded approach to ethics, transparency and conflict of interest in his other business and family entanglements.

Mr. Trump made the foundation announcement with typical braggadocio. “I gave millions of dollars to DJT Foundation, raised or recieved [sic] millions more, ALL of which is given to charity, and media won’t report!” he boasted on Twitter. “The DJT Foundation, unlike most foundations, never paid fees, rent, salaries or any expenses. 100% of money goes to wonderful charities!”

In fact, as The Post has reported this year, Mr. Trump apparently used the charity’s money to settle lawsuits involving his for-profit businesses. The New York probe is reportedly examining whether Mr. Trump violated a “self-dealing” provision that says nonprofit leaders cannot use their charity’s funds to help themselves, their relatives or their businesses. The Post also reported that, while the foundation did give money to charities and spent little on overhead, some of the expenditures were on rather dubious items, such as a $25,000 gift in 2013 to a campaign committee backing Florida Attorney General Pam Bondi (R) at a time when her office was considering whether to investigate fraud charges against Trump University. Although she never pursued the probe, and a consultant has said Ms. Bondi did not know about it when she solicited the gift, the payout looks questionable. So does the $30,000 spent by the foundation to buy two large portraits of Mr. Trump, and the $258,000 in foundation money used to settle lawsuits involving two of Mr. Trump’s for-profit businesses.

Mr. Trump now must tackle even bigger decisions. He has yet to detail how he will sever his ties with the business he built, but he should strive for a clean break, not only for propriety but also for his own credibility. If he hopes to be a productive leader, he will need all the political strength he can muster, and his capital could be badly sapped by questions about whether outsiders tried to buy influence through his family business. Mr. Trump long ago promised to make public his tax returns, as have other presidential candidates for years, but he has never done so.

It is hard to read Mr. Trump’s compass on these issues. On one hand, he has been outspoken in demanding a break from business as usual, including close ties between policymaking, lobbying and federal contracting. He promises to “drain the swamp” in Washington. However, he seems less eager to act when it involves his own business and family. Before the inauguration, Mr. Trump should declare a zero-tolerance policy toward conflicts of interest and impropriety — especially his own.