In Calfarm Ins. Co. v. Deukmejian (1989) 48 Cal. 3d 805, a contract clause challenge was made to Proposition 103, an initiative enacted in 1988 which made fundamental changes in the regulation of automobile and other types of insurance. (48 Cal. 3d at p. 812.) The extensive regulation of the insurance industry was a factor considered by the Calfarm court in discussing whether there was an impairment of contract. The court concluded that further regulation of the industry could reasonably be anticipated and that the impairment of contract was "relatively moderate and restrained." ( Id. at p. 830.) In applying these principles to this case, we weigh the degree of impairment to determine the magnitude of the public interest required to justify the impairment. ( Calfarm Ins. Co. v. Deukmejian, supra, 48 Cal. 3d at p. 830.) The court observed: " 'All presumptions and intendments favor the validity of a statute and mere doubt does not afford sufficient reason for a judicial declaration of invalidity. Statutes must be upheld unless their unconstitutionality clearly, positively, and unmistakably appears.' If the validity of the measure is 'fairly debatable,' it must be sustained." The California Supreme Court upheld a provision of Proposition 103, regulating insurers, which restricted the insurer's right to cancel or non-renew a policy. The court held that the impairment was not substantial: the regulation was "moderate and restrained," allowing insurers to continue to refuse to renew for nonpayment, misrepresentation, or a substantial increase in the hazard; it guaranteed insurers fair and reasonable rates; and it affected a "highly regulated industry, and one in which further regulation can reasonably be anticipated." (Calfarm Ins. Co., at p. 830.) In short, insurers challenged Proposition 103 on numerous grounds, including that the mandated insurance rate rollbacks were constitutionally confiscatory, i.e., deprived insurers of a fair return. The court agreed, rejecting the assertion, among others, that the rollbacks could be sustained as temporary emergency measures in the face of rapidly increasing rates. (Calfarm, at p. 821 the "asserted rise in insurance rates ... is not a temporary problem; it is a long term, chronic situation ..."; see id. at pp. 816-820.)