The New York Times published one of those stories Saturday night that can fundamentally alter a presidential race, reporting that Donald Trump may have avoided paying federal income taxes for up to 18 years. Little wonder then that it’s being called the first October surprise of the election cycle. There are several reasons why the report could amount to a devastating blow for the Republican presidential candidate. Here are the main ones:

1. Clinton appears to have been right, Trump was trying to hide something “terrible.” During Monday’s debate, Hillary Clinton went through several reasons why Trump may be refusing to release his tax returns. Whatever the reason, she concluded, it must be really bad. “And I think probably he’s not all that enthusiastic about having the rest of our country see what the real reasons are, because it must be something really important, even terrible, that he’s trying to hide,” Clinton said. The Times story fits right into this narrative.

2. What business acumen? A big part of Trump’s narrative of why he should be president is that he’s a great businessman who has managed to make lots of money throughout the years. He has vowed to transfer those business smarts to the White House. But the tax returns revealed by the Times that show he lost almost $1 billion in one year lend credence to those who have said Trump is not as successful as he claims to be and how his business dealings have hurt a lot of people along the way. The Clinton campaign has already seized on this a bit in its first press release after the Times story was released, saying the piece “reveals the colossal nature of Donald Trump’s past business failures.” Clinton could take this idea further and get under Trump’s skin by calling him a failed businessman at the next debate, which we all know he hates. As Slate’s Jacob Brogan wrote on Twitter: “Trump said he didn’t pay taxes because he’s ‘smart’. It turns out he didn’t pay taxes because he’s one of the worst businessmen in history.”

Trump said he didn't pay taxes because he's 'smart'. It turns out he didn't pay taxes because he's one of the worst businessmen in history. — Jacob Brogan (@Jacob_Brogan) October 2, 2016

3. He’s just another big shot taking advantage of a system that screws the little guy. Part of Trump’s appeal has always been that he knows Washington insiders have an unfair advantage over the little guy who always ends up getting the short end of the stick. But the Times story suggests Trump is one of those big shots who know how to game the system for their own personal benefit. Tax experts can very well argue (as they do) that none of what Trump did was illegal but that would seem to matter little when Clinton can make the argument that a man claiming to be one of the wealthiest businessmen in the planet didn’t pay any income tax while working families struggling to make ends meet had to pay up.

4. He refused to donate money to charity. Hidden inside the Times story is a little gem about something the three pages of Trump’s 1995 tax returns showed: “Mr. Trump declined the opportunity to contribute to the New Jersey Vietnam Veterans’ Memorial Fund, the New Jersey Wildlife Conservation Fund or the Children’s Trust Fund. He also declined to contribute $1 toward public financing of New Jersey’s elections for governor.” The Times didn’t analyze the candidate’s federal tax returns so it’s impossible to know how much he donated to charity that year. But his failure to donate to these charities helps Clinton make the case that Trump only watched out for himself.

5. The issue won’t be going away. Trump’s failures to release his tax returns have hung over his campaign for months. Now, attention on the issue will only intensify. And not just on how he’s the only candidate in 40 years to refuse to release his returns, but also on how he has flip-flopped on the issue. After all, during the primaries he had vowed to eventually release his returns only to back off that promise later. Trump has said he can’t release his returns because he is being audited, but everyone has called him out on that as just plainly false. Expect to hear a lot more about this in the coming weeks.

6. It comes after Trump’s terrible, horrible, no good, very bad week. Context is everything. Maybe Trump could have brushed off this latest bit of news if it weren’t for the fact that it comes at the end of what some are calling the worst week of any presidential campaign in recent memory. It all began with Trump’s terrible performance in the first presidential debate and then continued with him trying to justify the way he treated a former Miss Universe and a 3 a.m. tweetstorm that had a presidential candidate urging voters to check out a “sex tape.” And that’s without mentioning other potentially devastating news that came out this week, such as Newsweek’s revelation that Trump had illegal dealings with Cuba.

Read more Slate coverage of the 2016 campaign.

