I am talking about what tactics highly Authoritarian countries and rogue states use to keep their population docile and prevent them from rebelling against their regime.

Something I have noticed in common with nearly every major Authoritarian country (Russia, Uzbekistan, Syria, Iran, Eritrea, Sudan, North Korea off the top of my head) is that they always say that they're constantly at work at fighting an external enemy of some sort, and their rule is legitimized based on those claims. Let's take a look at who these countries/factions are "resisting"

Russia claims to be fighting against the US. Uzbekistan claims to be fighting against Islamic Extremism. Syria/Iran claim to be fighting against Israel. Eritrea claims to be fighting against Ethiopia. Sudan claims to be fighting the West. And North Korea claims to be fighting the US and South Korea.

With all of these countries mentioned aside from Uzbekistan, the country in question claims to be resisting another country of equal or greater strength.

So this is all leading into my real question... why is claiming to be resisting against a foreign power of equal or greater strength so effective at keeping the population you're ruling over largely docile?

It works because your evil regime is less evil than the evil  regime that your citizens think you're fighting.

Which makes sense, since many of these authoritarian states even admit to their populations that they're more authoritarian than they should be. Which in itself could be another card they play.

Seems pretty self-explanatory. Give the people something to hate more than the government.