story identification - Miniseries in post-rapture US with good/evil conflict

I remember seeing this dramatic mini-series in the late '90s-'00s, but it may have been created in the '80s. I believe it was an adaptation from a book by a well-known author.

The setting was in the US after some rapture-like event. I don't remember the cause, I just remember that there were a very small number of people left, and almost all of them were critical characters. The portions I remember involved traveling through the desert towards a big city (Las Vegas?), and I believe the final conflict was there in the city. The main story was about this final conflict/showdown between these people who were representing the forces of good and evil. There were definitely some religious themes as well.

There are only two characters I remember. The main character was your generic conflicted Everyman with good morals, so not much detail there. The other was a gentle-giant type who was big and strong but had the mind of a child. I think he ended up being very important towards the end.

Unfortunately that's all I remember right now, but I'm hoping it was popular enough to be obvious to someone. The one series I know it's not is Left Behind. The one I saw was not nearly as directly Biblical.

Answer

It is definitely a The Stand based on Steven's King novel with the same title.

There was no rapture - instead, a deadly biological weapon has been released which has killed 99% of the population (the virus is deliberately introduced to USSR and China to assure mutual destruction).

With time, two groups of survivors emerge: one group is made of people who were dreaming about an elderly woman called "Mother Abigaile", whom later go to create a "Free Zone" - a democratic society in the Boulder, Colorado. The second group follows Randall Flagg, an evil being with supernatural powers, who starts to rebuild an army.

Randall Flagg with/without makeup.

With time, both groups became aware of each other and the Free Zoners decide to send infiltrators to Las Vegas - all of them are quickly dispatched by Flagg, with an exception of Tom Cullen - a mentally challenged big man, who has been hypnotised (himself?) to believe that he has been cast out of the Free Zone.

You can see Tom Cullen in the background here:

With the conflict becoming inevitable, dying Mother Abigaile sends the remaining council members from the Free Zone to negotiate with Flagg, but one of them breaks a leg on the journey. The rest are captured by Randall's army and are about to be executed when one of Flagg's crazy followers brings a nuclear warhead. Flagg attempts to stop him using a ball of energy, but it is transformed into "a hand of God", which grabs and detonates the warhead, destroying Las Vegas.