The June 27 presidential debate sponsored by CNN requires candidates running outside the major parties to have qualified in states containing at least 270 electoral votes by June 20. This is an irrational requirement, because the traditional bulk of petitioning for independent presidential candidates is done later in the year than June 20.
For example, in 1992, Ross Perot was only on the ballot in states containing 119 electoral votes as of June 15. The authority for this statement is the June 15, 1992 print issue of Ballot Access News. It shows he was only on the ballot in Alaska, Arkansas, Delaware, Florida, Idaho, Kentucky, Maine, New Jersey, Tennessee, Texas, Utah, and Wyoming (12 states). He was finished petitioning in many more states on that date, but the state elections offices hadn’t checked his signatures yet.