The only constant about California is that it is constantly changing, and that axiom is being driven home this week.

Five years ago, California voters passed a constitutional amendment prohibiting same-sex marriages. However, in the wake of last week's U.S. Supreme Court ruling, hundreds of gay and lesbian couples are being married in the state. And polls indicate that were Proposition 8 on the ballot again, it would fail.

When Jerry Brown was elected governor for the first time in 1974, California was still an overwhelmingly white society, but on Monday, a gathering at the Capitol marked the historic emergence of Latinos as the state's largest ethnic group sometime this year.

Brown's 1974 election was something of a fluke, because during that era, California more often than not leaned Republican. Republican voter registration, however, has dropped to below 30 percent, and that's just about the party's share of legislative and congressional seats.

Within a few years, California's "declined to state" voters may outnumber Republicans.

California's rapid cultural, ethnic and political evolution has always been driven by a relatively high rate of population growth, but the most recent state and federal estimates confirm what the 2010 census revealed — our population isn't growing very fast anymore.

Three decades ago, California's population was increasing by 2-plus percent a year, but the rate is scarcely a third of that level today.

Foreign migration has slowed to a trickle, and we now lose more population to other states than we gain, offset only by births outnumbering deaths.

California's rapidly decreasing birthrate and a death rate that is destined to increase as the state's large baby boom generation ages could result in zero population growth, but the white population will continue to decline proportionally.

These trends also affect the state's economy. Slower population growth, for instance, lowers demand for housing and retail goods, and thus slows the flow of investment capital into consumer-oriented business.

But the aging of the white population, coupled with new money from the federal Affordable Care Act, will make the state's largest single economic activity — health care — even larger.

Nevertheless, California will continue to see economic segmentation — more haves, more have-nots and a shrinking middle class. One experimental Census Bureau method of measuring family economics tags California with the nation's highest rate of poverty. These changes, meanwhile, affect both state and local government revenue streams and the programs that they finance.

Significantly, Governor Brown chose Monday to sign legislation that will divert more state school aid into districts with large numbers of poor and/or English learner students who fall behind in academic achievement.

Dan Walters is a columnist for the Sacramento Bee.