This exactly. Except for cell phone location info, SCOTUS says when a company holds your data, that’s the company’s papers, and you have no Fourth Amendment rights in it. When it’s the president, ha ha, don’t be silly, of course it makes no difference who’s got the data. https://twitter.com/rob_lorenz/status/1281317491822800909

When it’s the president, SCOTUS cares about “the substance, not the shadow” and declares a huge swath of documents to be HIS information, even if they’re part of a third party’s business records. But in your case? Tough luck, peasant.

Ironically, SCOTUS cites its own recent Carpenter ruling, making a narrow exception to the “third party doctrine” for cell location records. Know what Carpenter definitely didn’t apply to? Bank and financial records! Because that’s where the third party doctrine comes from.

Obviously, this is *not* a Fourth Amendment case, so they’re not literally saying the president has different Fourth Amendment rights than the rest of us—they didn’t tell Manhattan DA Cyrus Vance he’d need a probable cause warrant to obtain Trump's financial records. Still...

…the contradiction in the underlying logic is striking. In the Mazar’s case, the majority just finds it obvious that Trump’s constitutional interest in certain private data doesn’t depend on who holds it. Barely gets a paragraph. But their authority for this obvious point...

…is a case that carved out a teensy tiny exception to a 40-year-old doctrine establishing *exactly the opposite* general rule. The general rule is that it makes all the difference in the world: you waive your constitutional rights in private data you share with a company.

Our entire legal regime for criminal investigations—and routine warrantless government access to citizens’ financial & telecommunications records—is HUGELY dependent on an argument that SCOTUS found so obviously stupid today that they laughed it off in a single paragraph.

SCOTUS today, on why it doesn’t matter that Trump’s records are in third-party custody: "Were it otherwise, Congress could side-step constitutional requirements any time a President’s information is entrusted to a third party—as occurs with rapidly increasing frequency."

That’s a good argument! Why doesn’t exactly the same reasoning apply when the government gets your private information from a bank, phone company, or ISP to “side-step” the warrant they’d need to search your papers (or devices)?

Apparently in the Fourth Amendment context, we’ve got to settle for the “shadow” of our privacy rights, rather than the “substance."