Another day, another bad idea wafting out of New Jersey.

Yesterday we mused about the Garden State’s troubling push to loosen patient privacy protections and give law enforcement officials easier access to the state’s prescription drug monitoring database to fight the opioid epidemic.

Today we’ll be talking about another drug — nicotine — and another harebrained plan to curtail its use: raising the age at which people can legally buy cigarettes from 18 to 21. A law doing just that is going into effect in New Jersey this fall, and some Pennsylvania legislators are reportedly considering fielding a similar bill in the General Assembly.

It’s a simple plan: give young people more time to really think about whether they want to play around with a tremendously addictive drug that will shorten their lives, give them a prematurely aged appearance and even harm those around them.

The Centers for Disease Control and Prevention says tobacco use is the leading cause of preventable disease and death in the nation. Cigarettes alone are responsible for more than 480,000 American deaths per year — one in every five deaths.

An estimated 36.5 million adults smoke cigarettes nationwide, a rate of about 15 percent. That’s down from nearly 21 percent in 2005. Smoking rates among America’s high schoolers have also declined significantly, from nearly 16 percent in 2011 to 8 percent last year, according to the CDC.

In Pennsylvania, however, about 2 million adults smoke, a rate of 21.3 percent; and nearly 12 percent of kids ages 12 to 17 smoke.

Tobacco use and nicotine addiction cost this country hundreds of thousands of lives and hundreds of billions of dollars each year. Pennsylvania’s share of that is about 22,000 people per year about nearly $7 billion in annual health care costs.

More must be done to keep young people from picking up this deadly habit.

But here’s the thing: treating people like children usually ensures that they’ll act like it. Look no further than this country’s unhealthy relationship with alcohol for evidence of that correlation.

Binge drinking is a scourge on college campuses across America. And what’s the legal drinking age in this country? Twenty-one.

Twenty-one hasn’t helped Americans develop a more responsible and moderate relationship with alcohol. It’s a cardboard stand-in for real, effective public health policy dealing with the risks and costs of alcohol use and abuse.

That applies to cigarettes as well. Federal statistics show that nearly 90 percent of adult smokers started before the legal age of 18. How would simply raising that number higher change anything?

Smoking rates among adults and young people are at historic lows precisely because society has refused to allow Americans to be treated like children when it comes to cigarettes.

We’ve outlawed glossy advertisements that promote smoking as cool and fun; we’ve pumped public money into serious awareness campaigns that give people vital information about what they’re putting into their bodies; and we’ve committed to protecting non-smokers by banning the practice in various public places.

None of that was easy, simple or achieved quickly. But it has produced dramatic results — unlike the nation’s anemic efforts to combat underage drinking and other risky alcohol-related behaviors.

The message should be crystal clear: if we want to drive smoking rates even lower, it’s going to take hard work and real policy. Slapping a new age limit on a pack of cigarettes is neither.