Covert intelligence is important, because it is a channel of information which cannot be seen or controlled as easily by adversaries as open source information

Covert intelligence is important, because it is a channel of information which cannot be seen or controlled as easily by adversaries as open source information does. But the very covertness also means these intelligence services are highly intransparent and poorly supervised. And poor supervision usually leads to poor results, as viewed by those who should be doing the supervision.