In this article, Newsweek wrote:
"At the Republican National Convention, GOP foreign-policy men made recommendations to whomever will be the next American president, on the most pressing issues abroad."

According to traditional rules, whomever, just like whom, is "used as the object of a verb or preposition." (The American Heritage Book of English Usage, pp. 49-50, Houghton Mifflin Company,1996) In the sentence above, whomever will be the next president is a nominal relative clause; thus, you need to determine what role the relative pronoun whomever plays in the relative clause, not in relation with the main clause in order to determine whether you should use whoever or whomever. If you look at the relative clause closely, you'll see that the appropriate relative pronoun needs to play the role of a subject, not an object. Therefore, whoever (=anyone who) will be the next American president is grammatically correct.

I do know that I rely on prescriptive grammar in pointing out this mistake. Some linguistis are opposed to prescriptive grammar, but I believe that they should become aware that language is a by-product of social life, which inevitably includes judgments about what is acceptable in a given society. In fact, if you ask any grammarian, he or she will agree that whomever should be replaced by whoever in the abvoe sentence.

You are kindly reminded that accuracy is still a virtue in this seemingly chaotic world.