This topic came up prior to the first debate. In order to allow them on the stage, one must redefine what measuring stick we wish to use for those of whom wish to have a podium. There are roughly 43 political parties in the U.S. If each one nominates a candidate and gets an equal amount of time, no one gets much substance in a 90 minute debate. If we only wish to allow the five major party candidates (Dem., Rep. Libertarian, Reform, Green) we must have a measuring stick that clearly shows why these five belong there, and the other 38 do not. Otherwise we end up with 6th party supporters making the same argument that 3rd party supporters are making now, only without clear guidelines. The current guidelines are available from the Federal Election Commission. One additional thing of note: the qualifications for being on the stage are the same as for qualifying for the $91.2 million campaign matching funds, so this could get absurdly expensive, very quick.