(FiveThirtyEight) In a few months, after Iowa and New Hampshire begin to winnow the field, the GOP nomination race could boil down to an epic final between a candidate with a more pragmatic image, such as Marco Rubio, Carly Fiorina or Jeb Bush, and a more conservative one, such as Ted Cruz, Ben Carson or Donald Trump.1

If that happens, the moderate finalist — like Mitt Romney and John McCain before him or her — will have a hidden structural advantage: the party’s delegate math and geography.

There are plenty of reasons to be cautious of national polls that show Trump and Carson leading. They may fail to screen out casual voters, for instance, and leaders at this point in past years have eventually tanked. But perhaps the biggest reason to ditch stock in these polls is that they’re simulating a national vote that will never take place.

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