Attorney General Eric Holder’s call for ending mandatory minimum sentences for low-level drug offenders has sparked a national debate on drug policy that should have begun 25 years ago.

During last Monday’s speech on drug policy reform, Holder repeatedly singled out “young people” as a special target, particularly “the fact that young black and Latino men are disproportionately likely to become involved in our criminal justice system — as victims as well as perpetrators.”

This is a common refrain — but increasingly untrue. Law enforcement and public health agencies data now shows that U.S. drug abuse and crime problems have been shifting to older and whiter demographics over the last two decades — creating new realities for debate and policy.

Unfortunately, national discussions of crime, gun violence and other vital social issues are continuing as if the last 20 years never happened.

Only one state, California, has kept reliable, complete arrest statistics over several decades by race, sex, offense and age. But California’s drug arrest and abuse trends often reflect (or are harbingers of) national trends, and in the Golden State developments are challenging every major premise of the drug-policy debate.

Younger Californians — especially African-Americans and Latinos — show plummeting drug offense arrest rates. They are now the only groups to have lower rates today than before the War on Drugs began 30 years ago.

From 1980 to 1990, drug arrests rose only modestly for whites. But for blacks, they more than doubled. Among African-Americans under age 30, drug busts rose from 24,000 to 36,000 during the decade. But the increase was even more pronounced for blacks who were age 30 and older, from 8,500 in 1980 to 31,000 in 1990.

Since the early 1990s, however, younger Californians — especially African-Americans under age 30 — showed enormous decreases. This took place even as drug arrests and imprisonments among older Californians continued to rise rapidly.

In 2012, just 9,100 California blacks under age 30 were arrested for drugs — a 75 percent decline since the early 1990s and a number and rate less than half that of 1980. Younger Latinos, whites, and Asians also had precipitous declines in drug arrest rates.

This decline was not just due to California’s 2011 reform that reduced possession of small amounts of marijuana to a mere infraction. Declines in arrests among young Californians were declining before that reform — and included large drops in arrests for other drugs and drug felonies as well. In its first two years, the marijuana reform (which applied equally to all ages) has accompanied large decreases in young peoples’ arrests for marijuana, other drugs and other crimes.

Yet whites age 40 and older have shown big increases in drug arrests in recent decades: From 12,200 in 1980 to 50,300 in 2012. Older African-Americans and Latinos also showed increased drug arrest — but not to the same extent as older whites.

These trends are confirmed by deaths from overdoses of illicit drugs. Numbers are soaring among California’s aging whites; rising slightly among younger whites and older African-Americans and older Latinos, and declining sharply among younger African-Americans and younger Latinos. In 2011, just 25 African-Americans and 115 Latinos under age 30 died from abusing illegal drugs, compared to 2,600 whites age 30 and older. Rates of drug deaths among middle-aged Californians are now six times higher than among teens and 20 to 29 year-olds.

The reasons for these dramatic changes are not fully clear. But they may include the decline in the crack cocaine and heroin epidemics among poorer urban populations since the 1980s and 1990s combined with an explosion in pharmaceutical drug abuse among both whites and blacks who are middle-aged. For still unknown reasons, younger people are not part of the pharmaceutical drug explosion. It is difficult to match these trends to policies or policy changes.

Nationally, statistics are much less complete, detailed or reliable. Those available from the FBI show that even as drug arrests skyrocketed among middle-aged Americans, they declined among African-American youths from a peak of 80,000 in 1996 to 35,000 in 2011.

Similarly, even as the number of state and federal prisoners imprisoned for drug offenses rose from around 25,000 in 1980 to 347,000 in 2005, before declining to 332,000 in 2011, younger African-Americans show a decline in imprisonments over the last two decades. Declining drug abuse among young people may play a large part in this development.

The implications of these changing trends for America’s drug policy are stark. Can elected officials and policy-makers shift from the now outdated politics and attitudes of blaming social problems, including drug abuse, largely on powerless subpopulations, such as minorities, young people and immigrants? Can more rigorous, evidence-based approaches be implemented?

California’s dramatic trends show a way out of the imprisonment-driven Drug-War strategy, which has helped lead to prison crowding crises and family and community disruptions. California is moving tentatively toward deincarceration of low-level drug offenders, reorienting local programs to manage older addicts and studying the encouraging trends among its very diverse young population.

The question is whether national authorities can adapt to stunning new realities.

PHOTO (Top): A customer rolls a joint made of half marijuana and half tobacco to smoke inside of Frankie Sports Bar and Grill in Olympia, Washington, Dec. 9, 2012. REUTERS/Nick Adams

PHOTO: Attorney General Eric Holder speaks during the annual meeting of the American Bar Association in San Francisco, California, Aug. 12, 2013. REUTERS/Stephen Lam

PHOTO (Insert B): Inmates walk around an exercise yard at the California Institution for Men state prison in Chino, California, June 3, 2011. REUTERS/Lucy Nicholson