Oregon has raised its smoking age to 21, lending more momentum to a national movement that has now registered wins in five states.

Gov. Kate Brown signed legislation bumping the age at which people can buy both traditional tobacco products and electronic cigarettes to 21. It marks the latest victory for public health advocates who have already seen the smoking age boosted to 21 in California and in Hawaii, overriding the objections of the tobacco industry. New Jersey and Maine both approved legislation earlier this year bumping the age to 21.

Those bills have passed despite critics arguing that Americans who are able to vote, buy guns, join the military and serve on juries should be able to buy cigarettes. California's law creates an exception for active-duty members of the military.

Tobacco use has steadily waned in the US, according to the Centers for Disease Control and Prevention (CDC), with the share of adult smokers declining from 20.9 per cent of American adults in 2005 to 15.1 per cent in 2015. But cigarette smoking remains a key driver of preventable deaths, killing some 480,000 people per year.

Substantially fewer middle and high school students are smoking cigarettes, according to the CDC, while e-cigarette use among high school students ticked up between 2011 and 2016. Preventing young people from starting a lifelong addiction is a central argument for raising the age.