Some businessman.

Donald Trump’s last pillar of credibility as a presidential candidate, his supposed brilliance as a businessman, crumbled over the weekend when the New York Times reported that he had racked up enormous business losses in the early 1990s — nearly $1 billion in income.

Trump’s monumental failure in business, coupled with an aggressive exploitation of tax laws that begs for closer scrutiny, apparently allowed him to avoid paying state and federal taxes for almost two decades. Even as he soared ahead with the good life.

EDITORIAL

Trump’s repeated promise that he would run our country like he runs his businesses just got scary. There’s something appealing about putting a business executive in the White House, but not a failed business executive. Trump has been able to maintain his lavish lifestyle — the private jet, the glitzy homes — thanks only to a remarkably forgiving federal tax code that favors people at the very top. Virtually every other taxpayer — the hundreds of millions of ordinary working Americans who don’t qualify for such excellent tax breaks — has covered Donald Trump’s bad bets.

More than ever, it is essential that Trump disclose his tax returns to see how he managed to pile up the $916 million income loss he reported in 1995. How legitimate was that write-off? Only by looking at those tax returns can we know whether Trump’s ability to avoid paying income taxes for so many years was proper and ethical.

However this plays out for Trump, the big lesson here is just how strongly the federal tax code favors special interests, such as super-rich real estate developers.

Let’s say, just hypothetically, that you are a small business owner who drives an old Camry to the office each day. If you run your business into the ground, will the Internal Revenue Service cover your losses? Or will you be lucky to hang on to your kid’s college education fund?

But the real irony would be if your small business had failed because Trump was a big customer. Trump has a long history of stiffing small contractors, refusing to pay. He knows they can’t afford to sue.

Donald Trump is anything but a brilliant businessman. The emperor has no clothes.

Follow the Editorial Board on Twitter: @csteditorials

Send letters to letters@suntimes.com