As a developer and business mogul, Donald Trump famously stiffed contractors, college students, bankers, and partners. But he forgot the first rule of living outside the law: Never stiff your lawyer. Even the Mafia knows that.

It’s not yet clear whether Trump deliberately failed to repay lawyer Michael Cohen for advancing hush money to former Playboy model Karen McDougal and porn actress Stormy Daniels, or whether Cohen and Trump just failed to figure out the choreography of laundering a reimbursement from Trump to Cohen. But either way, there was enough probable cause of possible criminal activity for the special counsel and the U.S. attorney in New York to raid Cohen’s files.

When lawyer and client are suspected of joint fraudulent actions, the usual lawyer-client privilege doesn’t apply. That’s well-established legal doctrine.

After the raid, Trump indignantly tweeted, “Attorney-client privilege is dead.” In this case—his own—he’s right. But in cases where the lawyer is not the suspected fraudster, privilege is alive and well.

It’s not smart to have your attorney blur the roles of criminal lawyer, deal-maker, and fixer. Now, having opened this door, Robert Mueller is also investigating Cohen for pursuing deals in Russia on behalf of Trump, based on the coziness of the Trump campaign and Vladimir Putin.

This case blends three longstanding Trump trademarks: sexual grotesquerie, shady deals, and stiffing creditors. How fitting that it could be the beginning of his final downfall