Since the first Republican debate of this cycle, back in 2003 August, television networks have tried to figure out how to draw a balance between candidates that deserve the spotlight of being in the primetime debate and candidates who aren't quite that popular but also aren't Deez Nuts.

In that first debate, it was the top polling candidates in recent national polls that made the cut. In the most recent debate, with the earliest primaries getting ever closer, CNN included polling from Iowa and New Hampshire, effectively ensuring that more moderate candidates -- who do worse in Iowa and in the national polls -- got a spot.

On Tuesday evening, Fox Business unveiled the criteria for its upcoming debate Jan. 14 in North Charleston, S.C. And they're intricate.

The top six candidates in the five most recent live-caller polls get to be in the main debate. So do the top five in the five most recent polls in Iowa and New Hampshire. Which means that as few as six candidates could participate in the main debate -- and that we may not know for certain until shortly before the Jan. 11 deadline for polls to be included in the calculus.

To make the point obvious, we figured out who would be in and out under these criteria for every day since July 1. At times, nine candidates made the cut. Slightly more often, it was six candidates, as it is today. Usually -- more than half the time -- seven candidates would have been able to participate.

Which is probably good news for candidates and viewers. There will still be an undercard debate, but without its most interesting participant, Lindsey Graham (who dropped out this week). If the debate were being set right now, the undercard would include six others: Carly Fiorina, Rand Paul, Mike Huckabee, John Kasich, Rick Santorum and George Pataki. A little better than a Pataki-Santorum-Huckabee contest.

But, again, we likely won't know who's in and who's out until shortly before the debate itself. Still time to improve, Jim Gilmore.