Make-Or-Break Time For GOP Presidential Field

(CNN) -- We will know a lot more about the GOP field of candidates for president very soon -- shortly after the Ames, Iowa, straw poll this weekend.

We'll probably see several dropouts and, at least with Rick Perry, a likely addition to the roster.The Ames straw poll is not a very good predictor of who the ultimate nominee will be (George H.W. Bush won the poll in 1979, Ronald Reagan was the 1980 nominee; Pat Robertson won the poll in 1987, George H.W. Bush was the 1988 nominee; Mitt Romney won the poll in 2007, John McCain was the 2008 nominee).

But it does have a tendency to fuel and give life to campaigns, and it has a second tendency to tell other candidates whether this year is worth their continued efforts or not. For example, Lamar Alexander and Dan Quayle both dropped out shortly after their low finishes in 1999 in Ames.

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