This is the week that the steady drip, drip, drip of details about Hillary Clinton’s server turned into a waterfall. This is the week that we finally learned why Mrs. Clinton used a private communications setup, and what it hid. This is the week, in short, that we found out that the infamous server was designed to hide that Mrs. Clinton for three years served as the U.S. Secretary of the Clinton Foundation.

In March this column argued that while Mrs. Clinton’s mishandling of classified information was important, it missed the bigger point. The Democratic nominee obviously didn’t set up her server with the express purpose of exposing national secrets—that was incidental. She set up the server to keep secret the details of the Clintons’ private life—a life built around an elaborate and sweeping money-raising and self-promoting entity known as the Clinton Foundation.

Had Secretary Clinton kept the foundation at arm’s length while in office—as obvious ethical standards would have dictated—there would never have been any need for a private server, or even private email. The vast majority of her electronic communications would have related to her job at the State Department, with maybe that occasional yoga schedule. And those Freedom of Information Act officers would have had little difficulty—when later going through a state.gov email—screening out the clearly “personal” before making her records public. This is how it works for everybody else.

Mrs. Clinton’s problem—as we now know from this week’s release of emails from Huma Abedin’s private Clinton-server account—was that there was no divide between public and private. Mrs. Clinton’s State Department and her family foundation were one seamless entity—employing the same people, comparing schedules, mixing foundation donors with State supplicants. This is why she maintained a secret server, and why she deleted 15,000 emails that should have been turned over to the government.

Most of the focus on this week’s Abedin emails has centered on the disturbing examples of Clinton Foundation executive Doug Band negotiating State favors for foundation donors. But equally instructive in the 725 pages released by Judicial Watch is the frequency and banality of most of the email interaction. Mr. Band asks if Hillary’s doing this conference, or having that meeting, and when she’s going to Brazil. Ms. Abedin responds that she’s working on it, or will get this or that answer. These aren’t the emails of mere casual acquaintances; they don’t even bother with salutations or signoffs. These are the emails of two people engaged in the same purpose—serving the State-Clinton Foundation nexus.