With an emphasis on the word "favor," her response is likely to be for the President's missile defense system. With an emphasis, instead, on the word "effectively," her remark is likely to be against the President's missile defense system. And by using neither emphasis, she can later claim that her response was on either side of the issue. For an example of the Fallacy of Accent involving the accent of a syllable within a single word, consider the word "invalid" in the sentence, "Did you mean the invalid one?" When we accent the first syllable, we are speaking of a sick person, but when we accent the second syllable, we are speaking of an argument failing to meet the deductive standard of being valid. By not supplying the accent, and not supplying additional information to help us disambiguate, then we are committing the Fallacy of Accent.
Never apologize for or otherwise undercut the argument you've made or leave your readers with the sense that "this is just little ol' me talking." Leave your readers with the sense that they've been in the company of someone who knows what he or she is doing. Also, if you promised in the introduction that you were going to cover four points and you covered only two (because you couldn't find enough information or you took too long with the first two or you got tired), don't try to cram those last two points into your final paragraph. The "rush job" will be all too apparent. Instead, revise your introduction or take the time to do justice to these other points.