Most people agree that there are too many people in the world to allow liberal catch-and-kill regulations in freshwater.  At the same time, to allow only "a single fish to be landed, whether it's kept or not" (as John suggests) would soon destroy any interest in fishing.  I believe it's important to at least attempt to give people a vested interest in our wild rivers and lakes... if we don't, people will cease to care what happens with them.  

I firmly believe in the value of catch-and-release fishing.  However, there are better and worse ways of practicing it.  Fishing with too light of tackle, "fighting" a fish to exhaustion, and demonizing spin fishing (when it typically offers the quickest and most efficient way of getting a fish to the net); these are a few of the sad tenets of the modern sportfishing paradigm.