In recent years there has been a fair amount of press about lawsuits brought under the California Voting Rights Act. As near as I can tell, this law essentially requires cities to draw council districts in such a way that the number of districts where the minority citizens-of-voting-age population (CVAP) forms a majority of the total district CVAP is roughly proportional to the total minority population as a proportion of the total population of the city. That is, the number of seats that should be "allocated" to minorities is determined by total population, but the determination of whether a given district is allocated to the minority is determined by the CVAP, not the total population. For instance, if a city has a 7-member council and 30% of the population is a minority group, two of the seats should be allocated to that minority; this means two districts must be drawn wherein the CVAP of that minority group forms a majority of the total district CVAP. (I am assuming here that other criteria for application of the law have been met, e.g., that there has been satisfactorily demonstration that the minority group is insufficiently represented.)
What I am curious about is whether it can happen that it is impossible to draw such districts due to wide demographic disparities between the total population and the CVAP, and if so, what is supposed to happen under the law.
To take a random example, according to data from the US Census, the city of Santa Maria has a total population that is roughly 71% Hispanic, while the CVAP is about 49% Hispanic. Supposing the city had a 7-member council, 71% would suggest there ought to be 5 out of 7 districts where Hispanics should constitute a majority to ensure proportional electoral representation. But because the Hispanic CVAP is only 49% of the overall CVAP, it could be difficult or impossible (depending on the geographical distribution of the population) to actually draw seven districts with equal total population while giving Hispanics a majority of the CVAP in 5 of them. (In fact Santa Maria has a 5-member council, but I'm just using these numbers to illustrate the kind of demographic situation I'm talking about.)
So what I'm curious about is, how is this sort of thing supposed to work? What happens if the demographics and the geography result in irreconcilable disparities between total population and CVAP? Or what happens if districts can technically be drawn to satisfy the requirements, but must be obviously and severely gerrymandered to do so? Has this question ever been raised?
I'm not actually sure that the California Voting Right Act strictly requires that cities play off the total population and CVAP in this way, but that appears to be the basis for some of the decisions that have taken place (see e.g. references to CVAP here). I would welcome an answer that clarifies the overall mechanics of exactly what cities must do to comply.
(Also, just to avoid any misunderstanding, I want to make clear that I'm not asking this to try to cast doubt on the CVRA or its goals. The reason I'm asking is that the city where I live recently underwent a redistricting to comply with this law, and asked citizens to come up with district maps meeting the criteria outlined above. I tried my hand and found it rather difficult to do, and I wondered if other cities with larger population/CVAP disparities might have even greater difficulties in achieving proportional representation.)