"[O]ur analysis in determining whether a particular constitutional enactment is a revision or an amendment must be both quantitative and qualitative in nature. For example, an enactment which is so extensive in its provisions as to change directly the 'substantial entirety' of the Constitution by the deletion or alteration of numerous existing provisions may well constitute a revision thereof. However, even a relatively simple enactment may accomplish such far reaching changes in the nature of our basic governmental plan as to amount to a revision also. In illustration, the parties herein appear to agree that an enactment which purported to vest all judicial power in the Legislature would amount to a revision without regard either to the length or complexity of the measure or the number of existing articles or sections affected by such change." ...
From a quantitative standpoint, it is obvious that Proposition 8 does not amount to a constitutional revision. The measure adds one 14-word section to article I -- a section that affects two other sections of article I by creating an exception to the privacy, due process, and equal protection clauses contained in those two sections as interpreted in the majority opinion in the Marriage Cases. Quantitatively, Proposition 8 unquestionably has much less of an effect on the preexisting state constitutional scheme than virtually any of the previous constitutional changes that our past decisions have found to constitute amendments rather than revisions....
[As to the qualitiative prong of the amendment/revision analysis,] the numerous past decisions of this court that have addressed this issue all have indicated that the type of measure that may constitute a revision of the California Constitution is one that makes "far reaching changes in the nature of our basic governmental plan," or, stated in slightly different terms, that "substantially alter[s] the basic governmental framework set forth in our Constitution." ... Proposition 8 works no such fundamental change in the basic governmental plan or framework established by the preexisting provisions of the California Constitution -- that is, "in [the government's] fundamental structure or the foundational powers of its branches." ...
Petitioners contend, however, that even if Proposition 8 does not make a fundamental change in the basic governmental plan or framework established by the Constitution, the measure nonetheless should be found to constitute a revision because it allegedly "strike[s] directly at the foundational constitutional principle of equal protection ... by establishing that an unpopular group may be selectively stripped of fundamental rights by a simple majority of voters." Petitioners' argument rests, initially, on the premise that a measure that abrogates a so-called foundational constitutional principle of law, no less than a measure that makes a fundamental change in the basic governmental structure or in the foundational power of its branches as established by the state Constitution, should be viewed as a constitutional revision rather than as a constitutional amendment. Petitioners suggest that their position is not inconsistent with our past amendment/revision decisions, on the theory that none of those decisions explicitly held that only a measure that makes a fundamental change in the state's governmental plan or framework can constitute a constitutional revision....
[But a]lthough a principal purpose of all constitutional provisions establishing individual rights is to serve as a countermajoritarian check on potential actions that may be taken by the legislative or executive branches, our prior decisions ... establish that the scope and substance of an existing state constitutional individual right, as interpreted by this court, may be modified and diminished by a change in the state Constitution itself, effectuated through a constitutional amendment approved by a majority of the electors acting pursuant to the initiative power....
[C]ontrary to petitioners' claim that a determination that Proposition 8 constitutes a constitutional amendment would represent a dramatic change in existing state constitutional principles, it is petitioners' proposal that radically would alter the long and firmly established understanding of the amendment/revision distinction embodied in the California Constitution. In basing their argument entirely on the circumstance that Proposition 8 has the effect of diminishing one aspect of a fundamental right of a group that this court has determined properly should be considered a "suspect class" for purposes of the state constitutional equal protection clause, petitioners in essence ask this court to read into the amendment/revision distinction embodied in the California Constitution a number of the distinctive elements of the state constitutional equal protection jurisprudence that have been developed and applied by this court in recent years. As we have seen, however, neither the history of the amendment/revision distinction in the California Constitution since its inception in 1849, nor the numerous cases that have applied that distinction, provide support or justification for such a radical transformation of the meaning and scope of the amendment/revision dichotomy.
That petitioners' proposal would mark a sharp departure from this court's past understanding of the amendment/revision dichotomy is further demonstrated by the circumstance that under petitioners' approach, the people would have the ability -- through the initiative process -- to extend a constitutional right to a disfavored group that had not previously enjoyed that right, but the people would lack the power to undo or repeal that very same extension of rights through their exercise of the identical initiative process. Thus, for example, had this court rejected the constitutional challenges to the existing marriage statutes in its decision in the Marriage Cases, and had the people responded by adopting an initiative measure amending the privacy, due process, and equal protection provisions of the state Constitution to guarantee same-sex couples equal access to the designation of marriage, that measure would be viewed as a constitutional amendment that properly could be adopted through the initiative process. But if an initiative measure thereafter was proposed to repeal those recently adopted changes to the state Constitution, that measure, under petitioners' approach, would be designated a constitutional revision, and the people would be powerless to adopt that change through the initiative process. Again, neither the history of the provisions governing the making of changes to the California Constitution, nor the many past cases interpreting and applying those provisions, support petitioners' assertion that the amendment/revision distinction properly should be understood as establishing such a "one-way street" or as mandating such a seemingly anomalous result....
In advancing the claim that Proposition 8 should be characterized as a constitutional revision rather than as a constitutional amendment, petitioners also rely heavily upon the circumstance that the measure was proposed directly by the people through the initiative process rather than by the Legislature, implying that under the state Constitution a measure proposed by initiative is more "constitutionally suspect" than would be a comparable measure proposed by the Legislature. Past California cases, however, provide no support for the suggestion that the people's right to propose amendments to the state Constitution through the initiative process is more limited than the Legislature's ability to propose such amendments through the legislative process. To the contrary, the governing California case law uniformly emphasizes that "'it is our solemn duty jealously to guard the sovereign people's initiative power, "it being one of the most precious rights of our democratic process"'" and that "'we are required to resolve any reasonable doubts in favor of the exercise of this precious right.'" The provisions of the California Constitution draw no distinction between the types of constitutional amendments that may be proposed through the initiative process as compared to those that may be proposed by the Legislature, and our past cases indicate that no such distinction exists.