There’s one easy way to make the main event more substantive while making the undercard debate more interesting. That is to raise the threshold for qualifying for the main debate.
For instance, if the networks were to place the cut off for qualification in the main debate at 5 percent support, that would leave six candidates (if looking at an average of polls compiled by RealClearPolitics): Carson, Donald Trump, Sen. Marco Rubio, Jeb Bush, Sen. Ted Cruz, and Carly Fiorina. The ultimate nominee is likely to come from this group, and if these were the only six candidates, there would be more room to get into actual substance and issues that are going to decide the nomination.
Meanwhile, there would be more reason to watch the earlier debate. Mike Huckabee, Sen. Rand Paul and Govs. Chris Christie and John Kasich would join the other lower-tiered candidates.
The candidates booted from the main stage may bark, but there are a number of reasons why they can’t legitimately complain. They have already had the opportunity to appear in three debates and have had months to campaign and boost their poll numbers.