Comment by AnthonyMouse

That's when the government is the one bringing the case to begin with. The issue is, if the government e.g. kills your spouse, why should the perpetrators get off scott free because the perpetrators want to keep something a secret?

Imagine the public tried to do that. Sorry, IRS/DoJ, the defendant is refusing warrants and subpoenas because it's a secret and without that you can't prosecute them.