Tolkien on the temptations of rule

“...our time is at hand: the world of Men, which we must rule. But we must have power, power to order all things as we will, for that good which only the Wise can see. ...

"A new Power is rising. Against it the old allies and policies will not avail us at all. There is no hope left in Elves or dying Númenor. This then is one choice before you, before us. We may join with that Power. It would be wise, Gandalf. There is hope that way. Its victory is at hand; and there will be rich reward for those that aided it. As the Power grows, its proved friends will also grow; and the Wise, such as you and I, may with patience come at last to direct its courses, to control it. We can bide our time, we can keep our thoughts in our hearts, deploring maybe evils done by the way, but approving the high and ultimate purpose: Knowledge, Rule, Order; all the things that we have so far striven in vain to accomplish, hindered rather than helped by our weak or idle friends. There need not be, there would not be, any real change in our designs, only in our means.”

—Saruman to Gandalf, in The Lord of the Rings, Book II, Chapter 2, "The Council of Elrond"

(I see now that many, many others online and elsewhere have seen in this quote the ongoing relevance it has to any number of important issues today; but since I'd yet to notice that, perhaps others haven't as well.)