Colorado’s registration requirement parallels the requirements in place in at least 19 States and the District of Columbia that candidate petition circulators be electors, see post, at 232, and the requirement of many States that candidates certify that they are registered voters. Like these regulations, the registration requirement is a neutral qualification for participation in the petitioning process. When one views the registration requirement as a neutral qualification, it becomes apparent that the requirement only indirectly and incidentally burdens the communicative aspects of petition circulation. By its terms, the requirement does not directly prohibit otherwise qualified initiative petition circulators from circulating petitions. Cf. Rosario v. Rockefeller, supra, at 758 (<HOLDING>). Moreover, as The Chief Justice illustrates in
holding that a nocontact order did not violate the right to freedom of association holding that the trial court did not err in denying a plea in abatement on grounds that individuals owning the balance of the working interest were not necessary parties holding that parties can stipulate that they were both parties to a contract and thus the real parties in interest even when one party did not sign the contract holding that hearing officers noting the parties agreement did not constitute a change in the parties legal relationship holding that time limits on enrollment in political parties did not violate the right of association because individuals were not prohibited from enrolling in parties