In light of current events, I wanted to suggest the following reading material. Yes, I have recommended many of these books in the past, but I will beat the drum about them yet again.
The Road to Damascus. No this is not about the Apostle Paul. It is a thinly veiled, military sci-fi treatise on the evils of communism cloaked in liberalism.
The Last Centurion: Another John Ringo classic. This one hits very close to home.
A State of Disobedience: I first read this back in 2004 while deployed to Iraq. It was spooky then. It is downright frightening now.
Caliphate: Another Tom Kratman novel. If you want to understand what the endgame of the "refugee" invasion of Europe means, you need to read this novel. A word of caution: it deals with very troubling subject material. Again, this is the process by which you can begin to steel your hearts and minds. Note I did not say harden. There is a difference. This one can be found for free on Amazon for the kindle app.