Here's an article from the Boston Globe about a theory of why the Japanese really surrendered to the U.S. in 1945. Historian Tsuyoshi Hasegawa of U.C.-Santa Barbara believes it was the Soviet Union's entry into the war in the Pacific that precipitated the surrender--not the bombs on Hiroshima and Nagasaki, as many believe.
It's a good cause-and-effect article, particularly because it shows that determining cause and effect can be a messy undertaking, and that even long-accepted conclusions can be open to debate. The article also goes into cause and effect on another level: "If the atomic bomb alone could not compel the Japanese to submit," writes Gareth Cook, "then perhaps the nuclear deterrent is not as strong as it seems"--and perhaps we should re-think our conviction that the atomic bomb, horrific as it was, was a necessary means to an end.
I think this article could yield good discussion from both a historian's perspective and a moral perspective.