Violations of the Confrontation Clause are subject to harmless error review with prejudice determined by excluding the evidence as to which confrontation was denied and evaluating the remaining evidence. Although the main mechanism implementing the right guaranteed by the Confrontation Clause is cross-examination, the right is not absolute. Before it can be curtailed, however, there must be some showing that it is necessary to overcome a defendant’s right to cross-examine. At trial, Ms. Barajas requested the address of the informant and sole witness against her. In denying the request, the court relied on the prosecution’s claim that to provide the address would compromise the informant’s future use as an informant and jeopardize her safety as no one likes tattle tails or snitches. The 9th Circuit ruled that by refusing to order disclosure, the state court made it impossible for Ms. Barajas to effectively cross-examine the informant. The error was not harmless because the informant was the only witness against Ms. Barajas.