Beyond common sense.

All you ever need to know about why civilizations become decadent:

A man who has experienced violence knows that, at its core, civilization is an agreement between men to behave well. That agreement can be broken at any moment; it’s part of manhood to be ready when it is. Men who have been in fights know about something that is rarely spoken of without snickering these days: honor. Men who have been in fights know that, on some level, words are just words: At some point, words must be backed up by deeds.

Above all, men who have been in fights know that there is nothing good or noble about being a victim.

Whereas men who haven't are indifferent about becoming a victim, which they eventually do become.

One commenter observers that the "denial of nature is the pestilence." Nature as being founded on competition and, ultimately, violence.

It's the point I make endlessly about sovereignty. NO spot on earth is controlled by any government but that they acquired that control – and maintain it – by force of arms, or the threat of it, whether their own arms or the arms of others. Pussy treaties are nothing without violence to back them up.

"Never Trust Anyone Who Hasn’t Been Punched in the Face." By Scott Locklin, Taki's Magazine, 9/7/11.