You don’t get to know who we arrested.
The Justice Department might be correct; revealing the names of those detained post-9/11 could be helpful to Al-Qaeda. Assuming, that is, that Al-Qaeda is incapable of figuring out whether or not cell members were arrested on its own. Which is actually less snarky an assumption than it appears; the answer depends on the nature of the cell structure. On the other hand, with a properly defined cell structure, Al-Qaeda leadership wouldn’t necessarily know that a given detainee was an Al-Qaeda member either.
But I digress. Let’s assume that there is some degree of risk associated with releasing those names.
That’s not a sufficient argument to keep ‘em secret.
The problem is this. If you don’t reveal the names, then you remove one of the checks and balances from the judicial system. You don’t need to assume that the Justice Department is acting in bad faith for that to be a bad idea. It’s possible for humans to make mistakes. There were US citizens in detention in Guantanamo Bay for a little while, for example. If we hadn’t known about that, we couldn’t have objected and they wouldn’t have been moved as quickly if at all.
These matters need to be public for the safety of the accused. Keeping them secret is a risk too. In order to make a strong case for secrecy, you need to show that the risk created by revealing the names is greater than the risk created by keeping them secret. Considering the recent report from the Justice Department’s Inspector General, it’s more than reasonable to expect the case to be made strongly.