This is from something I wrote somewhere else:
I came across something cool the other day. It has to do with a slightly different angle on Psalm 23. One way of looking at the phrase “The Lord is my shepherd” – evidently in the times that this was written the kings and rulers of different empires presented themselves as the “shepherd” of their people who would take care of all of their needs (not unlike politicians today, who try to convince voters by making all sorts of promises). So the Psalmist is saying, “the Lord is my shepherd”, not any earthly ruler. I like that way of looking at it. It doesn’t take away all of the other facets of God being our shepherd, it just adds to it.
So to all those out there who are hoping on human rulers, whether Democrat, Libertarian, or Republican, liberal, conservative, or moderate – The Lord, the creator of all things, the ruler over all – He is my shepherd. He is the one who will meet all my needs. I put my trust in Him, not in person or party.