The reason Intel agencies never saw the 5th column building up is it happened gradually in universities, in activist groups. Its presence became accepted and normal. Nobody took the march through the institutions seriously, even now.
The only resistance to the creeping radical project was grassroots opposition. It took the form of bloggers, alternative media and 'populism' outside the captured institutions. The radicals saw this inchoate enemy forming and called it 'hate' or the Deplorables.
The pandemic and the economy destroying response to it fortuitously created what they call in the trade a "revolutionary" condition. All that was needed was a spark. Seize the day. Seize the hour as Mao said.
What we have is a meeting engagement between the Gramscians vs the Minutemen. The radicals have lost their principal advantage, stealth.
Now that the Gramscian u-boat is on the surface the Minutemen should keep them there, spewing ridiculous statements, painting walls etc. They should take the initiative in ordinary life, going outside their precious institutions, in asymmetrical fashion.
"We must act as if the we -- our homes, families, work and beliefs -- were a fact. We defeat the Gramscian Empire by ignoring it".
