What is the test for appointing counsel for an indigent civil plaintiff?

Courts have discretion, pursuant to 28 U.S.C. 1915(e)(1) (1996), to appoint counsel for indigent civil litigants upon a showing of exceptional circumstances. "A finding of exceptional circumstances requires an evaluation of both the likelihood of success on the merits and the ability of the petitioner to articulate his claims pro se in light of the complexity of the legal issues involved." Terrell v. Brewer, 935 F.2d 1015, 1017 (9th Cir. 1991) (internal citations omitted). "Neither of these factors is dispositive and both must be viewed together before reaching a decision." Id. (internal citations omitted).