OK, from what I understand, the Hist pretty much can make the Argonians blood-crazed and do whatever the Hist desires (ie, beat up the Daedra, invade the Dunmer, etc.)

But could an Argonian resist? I mean, suppose an Argonian was walking down Whiterun and the Hist told him/her to go back to Black Marsh (how does the Hist do that?) could the Argonian resist it and move on, or would he/she have absolutely no choice? What happens if an Argonian resisted the Hist?

Basically, I know nothing about the Hist save for the fact that it is, I think, a huge magical tree that routinely tells Argonians what to do.

In the novels, Mere-Glim is able to resist the control of what was probably a rogue Hist tree in Lilmoth. IIRC he says it's like a constant, very persistent buzz in your mind, so resisting is unpleasant, and it may not be possible if all the Hist were united in something.

Also, the connection is stronger the closer they are physically to Black Marsh. Further away, the Hist's influence would be diminished.

I see.

So an Argonian in Skyrim may have better chance of resisting the influence than an Argonian near the borders of Black Marsh.

I should re-read the novels to be sure. I honestly don't remember Mere-Glim resisting any Hist. But it must be annoying, I bet.

This. If your Argonian is in Whiterun, the power that the Hist hold over him is greatly diminished, since he is far from Black Marsh. He'd likely be able to ignore their calls pretty easily, should he choose to. And if he's in Sovngarde, Apocrypha, or the Soul Cairn, he wouldn't be able to even hear their call, so distant are these places.