From what is arguably the most copy-edited part of the NYTimes, the op-ed page, this infelicity from a man who is otherwise a hero, Nicholas Kristof: ”For the general election, Intrade predicts that the Republican nominee (whomever it ends up being) has a 46 percent chance of winning the presidency in November.”

I take “ends up being” as a copula. Consider, for example: Boys will be boys. Boys become boys. Boys end up being boys.

If so, “ends up being” links two nominatives or subjects: “it ends up being whoever” = “whoever it ends up being.”

Interestingly, our ears might object less to “it ended up being them” when the prescriptive rules demand “it ended up being they.” The problem with “whomever” is that it is both less acceptable and fussier than “whoever” — a mistake according to both descriptive and prescriptive approaches to grammar.