The insurgent hides in plain sight.

Geneva Conventions, the so-called rules governing warfare, require combatants to wear uniforms or, at a minimum, bear arms to distinguish themselves from civillians.

The insurgent will not do this, for it would eliminate his only advantage--invisibility.

To take away the invisibility of the insurgent, make a perfect list.

Abraham Lincoln wrote, when laying out the strategies for winning an election--

"Organize the whole state, so that every Whig can be brought to the polls...
...Divide (the) country into small districts, and... appoint in each a subcommittee.
...Make a perfect list of all the voters and... ascertain with certainty for whom they will vote.
...Keep a constant watch on doubtful voters, and... have them talked to by
those in whom they have the most confidence.
...And on Election Day, see that every Whig is brought to the polls."

So to must the counterinsurgent follow these steps.  An entire nation or province is too large, but a Company sized area of operations can be organized and a perfect list, complete with photos and possibly biometric data, developed and their family and political loyalties ascertained with a degree of certainty.

A constant eye can be kept on those who are suspicious.  Have them talked to by those whom they trust and the counterinsurgents trust.

If evidence is obtained that they are insurgents, do not arrest them right away as they may unwittingly lead you to more.

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