Nancy Reagan, a former Hollywood actress and the widow of President Ronald Reagan, died at her home in California on Sunday at age 94, leaving behind a legacy as one of the most influential — and controversial — first ladies in American history.

The Reagans, who were in the White House from 1981 to 1989, are often heralded as setting the conservative standard for the decades to come, embodying neoliberalism and other philosophies that modern Republican presidential candidates often invoke to attract voters. They also presided over the sharp escalation of America's war on drugs, which led to an era of tough-on-crime rhetoric and draconian policies that swelled the US prison population.

While Nancy Reagan was known for many things — including her glamorous taste in high-end fashion and her belief in astrology — she is perhaps best remembered for her tireless crusade against drugs. One of the most defining moments of the Reagan administration was when Nancy Reagan, clad in red with perfectly coiffed strawberry blond hair, appeared on television screens across the country, earnestly warning viewers about the dangers of drugs and urging Americans to be vigilant about reporting drug use to authorities.

"For the sake of our children," Reagan said, "I implore you to be unyielding and inflexible in your opposition to drugs."

"Drug criminals are ingenious," she added. "They work every day to plot a new and better way to steal our children's lives, just as they've done by creating crack."

In 1982, during a radio address to the nation on Federal Drug Policy, Ronald Reagan stressed the seriousness of the drug epidemic to listeners, which he described as "an especially vicious virus of crime." He then turned to Nancy to tug at the country's heartstrings.

"Nancy returned from a trip to Alabama, Mississippi and Arkansas," Reagan said in the broadcast, "one of the many trips she's made, talking to young people and their parents about the drug epidemic. Well, I thought it might be fitting if she told you herself of what she's learned about the drug problem."

"To everyone at home," Nancy Reagan told listeners, "I have to tell you that few things in my life have frightened me as much as the drug epidemic among our children. I wish I could tell you all the accounts I've heard — stories of families where lying replaces trust, hate replaces love; stories of children stealing from their mothers' purses; stories of parents not knowing about drugs, and then not believing that the children were on them, and finally not understanding that help was available. I've heard time and again of children with excellent grades, athletic promise, outgoing personalities, but who, because of drugs, became shells of their former selves.

"I won't burden you with all the terrifying statistics, but there's one that's especially troubling," she continued. "While the health of most Americans has been improving, young people between 15 and 24 have a higher death rate than 20 years ago. And alcohol and drugs are one reason for this."

Nancy Reagan soon became the face of the "Just Say No" campaign. During one of her trips to California, she was reportedly asked by an elementary schoolgirl what to do if someone offered her drugs.

"A little girl raised her hand," Reagan recalled, "and said, 'Mrs. Reagan, what do you do if somebody offers you drugs?' And I said, 'Well, you just say no.' And there it was born. I think people thought we had an advertising agency over who dreamed that up — not true."

By 1988, more than 12,000 "Just Say No Clubs" had formed in schools across the country. Government-funded anti-drug commercials tried to scare kids away from recreational drug use, while warning parents about the horrible things that would happen if their kids started getting high.

The campaign was a cornerstone of the nation's war on drugs. The war was actually declared by by President Richard Nixon back in 1971, but it was Reagan who really set the wheels in motion, as the popularity of cocaine continued to boom, crack cocaine emerged on inner city streets and drug cartels south of the border became increasingly powerful.

In 1986, Reagan signed the National Crusade for a Drug Free America, an anti-drug abuse bill that took a zero-tolerance approach to drug use and distribution. It caused America's incarceration rate to skyrocket. Tough sentencing remained the weapon of choice in the fight against drugs for decades. The US currently has the highest incarceration rate of any nation in the world, and about half of all federal prisoners are locked up for drug crimes. Only in recent years, during the Obama administration, has the nation's drug policy shifted from criminalization to rehabilitation.

The effectiveness of the "Just Say No" campaign has been subject to some debate. According to the Reagan Foundation, cocaine use among high school seniors dropped from 6.2 percent in 1986 to 4.3 percent. But critics of the campaign say that it only served to create hysteria around drugs, and that touting abstinence isn't the best approach. A 2009 survey looked at teenagers who enrolled in DARE programs (the acronym stands for Drug Abuse Resistance Education), and found that participants were just as likely to use drugs as those who received no abstinence education.

A little girl raised her hand and said, 'Mrs. Reagan, what do you do if somebody offers you drugs?' And I said, 'Well, you just say no.'

Critics of abstinence programs often favor harm reduction approaches, which seek to educate users about safer drug use. While marijuana use has increased since 2007, according to the National Institute on Drug Abuse, use of most other types of drugs either stabilized over the past decade or has declined.

Still, America has continued to spend billions of dollars each year fighting the losing battle in the war on drugs. According to the Drug Policy Alliance, the US spends more than $51 billion annually on the war on drugs, and more than 1.5 million Americans were arrested in 2014 for drug law violations. Around 83 percent of those arrests were for minor possession of illicit substances.

Meanwhile, drugs are as easy to get as ever in the US, and tens of thousands of people across Latin America have died in drug-related violence as countries fight their own drug wars backed by US taxpayer dollars. More than 100,000 people have died in Mexico's drug war alone since 2006. It's those sorts of sobering statistics that make Nancy Reagan's message to Americans in 1990 seem absurd.

"Say yes to life," she said, "and when it comes to drugs and alcohol, just say no."

Follow Tess Owen on Twitter: @misstessowen