The saga of Donald Trump’s secret tax returns has consumed US politics for over a year. Every president and major presidential candidate since Jimmy Carter has released their tax returns to the public, but Trump has never been a big fan of tradition or precedent. He has repeatedly refused to allow the American people the chance to validate his bombastic claims about his personal wealth and generous philanthropy, and concealed evidence that could dispel – or validate – rumours about his shady business dealings in Russia and elsewhere.

Last night was supposed to clear all that up. Rachel Maddow from MSNBC announced that the network had obtained a leaked tax return from 2005. This was the chance to answer the questions the world has spent a year asking, and find out what Trump has been trying so hard to hide once and for all.

What did we learn? Nothing.

The two-page document, published by journalist David Cay Johnston and broadcast on MSNBC, was brief, incomplete, and almost entirely useless. The headline figures are that, in 2005, Donald Trump earned $150 million, but declared a loss of $100 million. He and his wife Melania paid $5.3 million in federal income tax, and an additional $31.2 million in Alternative Minimum Tax – a tax designed to prevent wealthy people from using deductions and loopholes to reduce their tax bills. In total, Trump paid $38 million in tax on an income of $150 million. That’s an effective tax rate of 24 percent – lower than the tax brackets for high earners, but higher than the average American.

Here’s what we haven’t learnt from the leaked tax return: How was that money earned? Which companies, both in the US and overseas, does Trump have dealings with? Is he financially linked to any parties that have benefited or will benefit from the legislation he is passing as president? How will his businesses (now under the management of his sons but still owned by him) be affected by any future tax changes the president enacts? Can his claims that he has given over $100 million to charity over the years be substantiated? Which charities? Which individuals and organisations does he owe money to now, and how could that impact his decisions around domestic and foreign policy? What exactly were his business dealings with Russia, and is there concrete evidence that all ties have now been cut?

Remember, the document aired last night was just from a single year, over a decade ago. It would have been impossible to clarify the answers to any of these questions with so little evidence. But that didn’t stop MSNBC and the entire US media from treating it as the revelation of the century.

Trump’s team has played this one well. In a statement, the White House said the tax return had been “illegally” published, but pointed out that all the document proves is that Tump paid the correct amount of tax in 2005. There is a slight controversy in that the AMT, which raised Trump’s tax bill to a reasonable amount, is one of the mechanisms Trump has said he wants to eliminate as president, but that is a trivial matter compared to the other looming questions.

In fact, this is such a non-story that there have been suggestions that Trump himself was responsible for the leak. It certainly wouldn’t be unprecedented – as a businessman, Trump was infamous for leaking positive stories about himself to the press. Even Johnston, the reporter who received the document anonymously in the mail, acknowledged that this is a possibility, telling Rachel Maddow: “It’s entirely possible that Donald sent this to me. Donald Trump has over the years leaked all sorts of things… Donald has a long history of leaking material about himself when he thinks it’s in his interest.”

Essentially, what this story has done is confirm Trump supporters’ worst instincts about the media, which they see as jumping on anything that could make the president look bad, while the document actually paints Trump himself in a fairly positive light. And suddenly, the narrative of a shady businessman who is hiding damaging information about his interests has shifted to that of a successful entrepreneur under fire for no reason. The other questions – the foreign deals, the conflicts, charitable claims, the potential for kickbacks and corruption – have been entirely swept under the rug. So has the revelation yesterday that, despite Trump’s promises after the election to donate his presidential salary to charity, he has failed to do so.

There are so many crucial things America and the world need to know about Donald Trump’s financial background. But last night, the media got played. We all need to do better next time.