.I don't know - I kind of see the Rangers as a people unwilling to allow themselves to be corrupted. They are sworn enemies of Sauron and all he represents. I don't see them as being willing to do anything that would ally them in any way with the shadow that they are fighting. They're saving the Shire from having to live the kind of life you live when orcs are a threat, but for them, I don't think that would mean giving any room for the shadow. Its the hard life in the wild they have to live, endangering their lives, etc., that they're saving the hobbits in the Shire from.
The Rangers of the North might be resistant to the Shadow by cultural inclination, but they are still fallible Men and would not be incorruptible They can't all be Aragorn even if he represents the ideal..