Oregon has become the fifth state to raise the legal age to buy cigarettes to 21.

Gov. Kate Brown, a Democrat, signed the bill into law early this month. It bars the sale of tobacco products to people younger than 21, effective Jan. 1, 2018.

Hawaii and California were the first two states to pass such a law. In July, New Jersey joined them, and last week, Maine enacted a law after legislators overruled a veto by Gov. Paul LePage, a Republican who called the bill an attempt at “social engineering.”

In most states, the legal age to buy tobacco products is 18; in a few, it is 19.

Supporters of a stricter standard say raising the legal age to 21 would save lives as well as cut medical costs for states. They point to a 2015 Institute of Medicine report that predicted that raising the age to 21 would reduce smoking by 12 percent by the time today’s teenagers are adults. It also would result in about 223,000 fewer premature deaths.

But opponents say a change would hurt small businesses, reduce tax revenue and violate the personal freedom of young adults who are legally able to vote and join the military.

In the past several years, a growing number of local governments have taken action on their own to boost the legal age to 21.

Stateline is an initiative of the Pew Charitable Trusts.