Acting White House Chief of Staff Mick Mulvaney sat down with CBS News’ Major Garrett this week for a podcast interview that covered a fair amount of ground. Of particular interest, though, was the exchange that began at the 23:12 mark of the conversation.

The host noted that the Treasury Department has refused a congressional order to turn over Donald Trump’s tax returns, and Garrett asked why. This was the exchange that followed:

MULVANEY: Because they are not entitled to see them by law. By the way, they know, especially on this one, they know they’re never going to get these documents. This is a pure show-pony-type of situation. They know the legal reasons they can get those documents – GARRETT: Legitimate legislative function. MULVANEY: Right. And they’re not even close to that… They’re just doing this to make the president look bad. They don’t care. This is not about information about the president. Keep in mind, all of the president’s financial holdings, by law, are disclosed. Want to know what the president owns? Want to know how he makes money? All of that stuff is, by law, I have to fill out my form by the end of next week. So does he. This is just about trying to embarrass the president. GARRETT: What’s embarrassing about his tax records? MULVANEY: That’s what they want to know. GARRETT: But what is it? MULVANEY: I don’t know because I’ve never seen GARRETT: Is there something embarrassing about his tax records? MULVANEY: I have no idea and I don’t care.

Oh my.

First, when Mulvaney says Congress is not “entitled” to the president’s tax materials “by law,” that’s true, just so long as one overlooks the law. In reality, existing federal law, which has been on the books for nearly a century, says the Treasury Department “shall furnish” the tax materials in response to a formal request from one of a handful of congressional lawmakers.

That formal request has been made, and at least for now, it’s been ignored despite the letter of the statute.

Second, Mulvaney suggests Trump’s legally required financial disclosure forms show “how he makes money.” That’s not quite right: disclosure forms show what the president has, not how he got it.

To know more about the sources of his wealth, we’d need – let’s all say it together – his tax returns.

But it’s Major Garrett’s good follow-up question that stands out for a reason: the White House’s acting chief of staff is convinced that the effort to obtain Trump’s tax returns is intended to “embarrass the president,” which naturally leads one to wonder why Trump would be embarrassed by his tax returns.

Mulvaney apparently didn’t see this line of inquiry coming, so he was left in an awkward spot: Democrats are trying to embarrass Trump, but his chief of staff has no idea why Trump would be embarrassed by his own tax materials.

And, Mulvaney added, he doesn’t care.

The South Carolina Republican’s indifference notwithstanding, given everything we’ve learned of late about Trump’s financial life, there are all kinds of reasons for the rest of us to care.