When does a person become an adult? It depends. Last month, Congress enacted a new law raising the nationwide legal limit for buying tobacco products from 18 to 21. The change also applies to electronic cigarettes and vaping products that heat a liquid containing nicotine. The bill was signed by President Donald Trump on Dec. 20.

At least 19 states had already restricted tobacco purchases to people 18 and older.

“This is a major step in protecting the next generation of children from becoming addicted to tobacco products,” Dr. Stephen Hahn, commissioner of the Food and Drug Administration, tweeted.

Because the change in legal age increased an age limit in an existing law, it went into effect immediately upon the president’s signature, according to the FDA’s interpretation.

The sudden change caused some confusion for some West Virginia retailers who sell tobacco and vaping products. Employees of several stores told HD Media reporter Fred Pace they were unsure what the details are of the new law. They were told a change has been made, but getting guidance on what the new restrictions are has been slow in coming.

The federal law preempts what had been West Virginia’s legal smoking age of 18. This year, two bills were introduced in the Legislature to raise the legal smoking age from 18 to 21. They would have excluded active-duty military members who are at least 18 years old. Neither bill failed to gain support, so they died.

Smoking is on a downward trend, and that’s good. It’s an addictive habit that can lead to health problems. The same goes for chewing and other forms of oral use of tobacco.

Anti-smoking advocates say higher age limits make it more difficult for older teens to get tobacco. That increases the likelihood they will never pick up the habit, they say.

One school of thought says some kids will always want to smoke, the same as they get around legal restrictions on buying certain kinds of alcoholic beverages. And there are people who say if you can die for your country at 18, you ought to be able to smoke.

That’s fine, but there’s another question that must be answered, and it goes back to the question above: When does a person become an adult and is assumed to be competent to participate in adult activities?

The legal age of adulthood is a constantly moving target. You can drive a car at 16, but you can’t smoke or drink. The age of consent for sexual activity varies by state, from 16 to 18.

Indoor smoking bans are a good idea, and few people if any want to go back to the days when people could smoke any time, anywhere. Workplaces, theaters and other places where people interact are much healthier now than when nonsmokers had to deal with a haze of smoke.

On the surface level, increasing the smoking age probably is a good idea, but the way Congress went about it was wrong. Tucking it into a huge spending bill whose purpose was to keep the federal government operating was wrong. The end result was a surprise, and people had little time to prepare.

Individual states were already on their way to increasing the minimum age for buying tobacco products. Ohio took that step this year. West Virginia probably would have in a few years.

Young people are used to the fact that adulthood comes in steps. Drive a car, buy a beer, smoke a cigarette — adulthood comes in discrete steps. Buying tobacco and hard liquor now form the upper boundaries of that process.