What is the legal test for appointing counsel for an indigent petitioner in a habeas corpus proceeding?

This court is further authorized to appoint counsel for an indigent petitioner in a habeas corpus proceeding if the court determines that the interests of justice require the assistance of counsel. See Chaney v. Lewis, 801 F.2d 1191, 1196 (9th Cir. 1986); 18 U.S.C. 3006A(a)(2)(B). However, "[i]ndigent state prisoners applying for habeas corpus relief are not entitled to appointed counsel unless the circumstances of a particular case indicate that appointed counsel is necessary to prevent due process violations." Chaney, 801 F.2d at 1196. In assessing whether to appoint counsel, this court evaluates the petitioner's likelihood of success on the merits as well as the ability of the petitioner to articulate his claims without counsel, considering the complexity of the legal issues involved. See Weygandt v. Look, 718 F.2d 952, 954 (9th Cir. 1983).