Setting ballot access criteria too low results in a plethora of frivolous candidates on the ballot which causes confusion and wastes the time of voters. Setting ballot access criteria too high protects incumbants against fair competition by restricting the rights of voters, candidates, and political parties.
In many U.S. states, ballot access laws keep frivolous candidates off the ballot while protecting the rights of third party candidates (e.g. of the Constitution, Green, and Libertarian parties) to run for office and the rights of voters to vote for them. In other states, Democrats and Republicans collude to impose extremely restrictive ballot access laws not to keep frivilous candidates off the ballot, but to keep all other parties off the ballot. Both state and federal courts often nullify overly restrictive ballot access laws on various constitutional grounds.
As an example of how ballot access laws are designed by Republicans and Democrats to protect Republicans and Democrats from competition, as of November, 2003, a Republican or Democrat wishing to be on the presidential ballot in all fifty states needs to collect a minimum of 23,500 valid signatures. However, a candidate of a new party needs to collect a minimum of 625,000 valid signatures.
An even more extreme example (Title 26, sections 5-112 and 6-106) may be found in Oklahoma where candidates may appear on the ballot by paying a filing fee -- except for voters who are registered Libertarian or Reform, who must collect a minimum of 51,781 valid signatures.