Imagine you are fifteen years old. You have been keeping a journal for as long as you can remember. It is one of those journals with a hard cover and a lock on it; nobody else is meant to read it.

In that journal, you have written about your frustrations with your parents, the friend who betrayed you, the boy or girl whom you really like but who doesn’t even know you exist, the trouble you have in your worst school subject, and how proud you felt when you got an A. You write about everyday things like the meatloaf you had for supper, and you write about things that really matter like how the new immigrant kid at school is getting teased. It is how you organize your thoughts, and it is for you alone to read.

Then imagine that, while you weren’t looking, someone you know only slightly walked into your house, took the journal out from under the mattress and then walked out with it. Not only that, but they broke the lock, read your journal, and shared it all with their friends, laughing at the stupid stuff and the secrets.

There’s no way to make that right. They could give you back the journal, but it’s already too late. The journal is gone and so is the private intimacy of the writing.  They didn’t just take what you wrote in the past, they changed what you might have written in the future. You will never have that same writing freedom again.

That’s how I imagine they feel at the Democratic National Committee. When the Russians hacked into the D.N.C. computers, they changed for ever the way that political organizations plan and communicate their strategies. Embarrassing emails were released to the media and Wikileaks dumped online a whole lot of files to distract everyone at a crucial time. The electoral preparation system that people thought they kept hidden has been hijacked, used, and mocked.

We cannot trust any political party’s election strategy from now on to be planned in the same ways as before. The processes weren’t perfect but, like the diary under the mattress, they were secret and the secrecy allowed for creativity.

Russian hackers didn’t just steal a lot of embarrassing emails, they also stole the freedom of expression that comes with privacy. And that is the greatest loss of all.