Robert Mueller isn’t just going to destroy Donald Trump. He’s going to expose Trump’s most humiliating secret.

For some people, there are worse fates than losing their job, or their reputation, or even their freedom. They have that one deep dark secret that, if it ever surfaced, would destroy them psychologically. They’re willing to go to any length, take any unreasonable risk, to prevent that secret from coming out. It often ends up being their undoing. And that brings us to the case of Donald Trump, whose most humiliating secret is on the verge of being exposed.

No, it’s not the Pee Pee Tape. Donald Trump is clearly afraid of his sexual fetishes being exposed, as evidenced by the time he called up then-FBI Director James Comey specifically to insist that he hadn’t done anything with “Russian hookers.” But there’s something Trump fears even more, and we saw during the campaign that he was willing to risk losing the election just to keep it a secret: he’s broke.

Trump was unwilling to release his tax returns, even though it generated the kind of suspicion and skepticism that risked costing him votes in the process. We know he’s been audited so many times over the years that if he were cheating, he’d have been caught by now. Instead, what he was really trying to hide is his net worth, or lack thereof. There are numerous signs that Trump went flat broke after the 2008 crash.

He had to bankrupt and begin selling off his casino company in 2009. That’s when he stopped donating to his own foundation according to its tax records; the only reason to do this was that his income was so upside down, there was no need to continue generating write-offs. He had to start borrowing from foreign banks, because his American banking partners all knew he was washed up. In the end, Robert Mueller will expose that Trump’s debts are so large, he’s not a billionaire. Instead he’s flat broke. And for Trump, that’s a worse fate than everything else that’ll happen to him.