Before the Cigarette Act of 1965, the picture advertisements painted of smoking was a rosy one. “11,105 doctors say Lucky Strikes prevent throat irritation,” boasts one ad from the 1920s. Others show men in lab coats puffing away, noting, “More doctors smoke Camels than any other cigarette.”

It was a few decades before those claims went up in smoke. A study presented at the 1954 gathering of the American Medical Association gave some of the earliest firm evidence that smokers died at higher rates than nonsmokers. That same year, a division of the American Public Health Association adopted a resolution urging people to stop smoking cigarettes, one of the first pronouncements by a major scientific body in America linking cigarettes to lung cancer.

Thus started the long war over how the public views the risks of tobacco. Cigarette brands lost no time in forming the Tobacco Industry Research Committee, which began to fund—and broadly publicize—rival scientific studies. “The vast majority of smokers never get lung cancer,” the committee’s chairman, Timothy V. Harnett, wrote in 1958. “There is no simple cause-and-effect mechanism resulting from cigarette smoking.”

The first round went to the tobacco industry, hands down. National consumption went from 368.7 billion cigarettes per year to 490 billion between 1954 and 1961. By 1962, Surgeon General Luther L. Terry—a smoker himself—had appointed a panel on smoking, and two years later issued the first Surgeon General’s Report on Smoking and Health. It set out in no uncertain terms that smoking caused lung cancer and laryngeal cancer in men, was a probable cause of lung cancer in women and was the most prominent cause of chronic bronchitis.

Although the findings were based on more than 7,000 research articles, lawmakers from tobacco-rich states cried foul. Representative Harold D. Cooley from North Carolina proposed that the government invest $5 million in more serious research to “dispel all the disquiet about smoking and associate good health with the enjoyment of tobacco.”

The impasse was broken by an unlikely agent for public health: the Federal Trade Commission. Failing to warn consumers of cigarettes about health hazards, it said, constituted an unfair trade practice, and the agency recommended that health warnings be featured both on cigarette packaging and in advertising.

So in 1965, Congress passed the Cigarette Labeling and Advertising Act. The law required packaging to carry the warning “Caution: Cigarette smoking may be hazardous to your health.” Because of compromises needed to get the bill passed, no other restrictions on advertising made the final cut. Instead, advertisers agreed to a self-imposed code that would keep cigarette advertising out of college publications, put an end to endorsements from sports heroes who might appeal to youth, and—most important—eliminate unfounded claims about health benefits.

The battle was far from won. Legislative progress only spurred more inventive cigarette marketing. When Congress banned cigarette advertising on radio and television in 1969, tobacco companies turned their efforts toward broadcast sporting events, such as the Virginia Slims women’s tennis series. The Comprehensive Smoking Education Act of 1984—signed into law by President Reagan, himself a Chesterfield spokesman in the early 1950s—brought health warnings to print advertising. The tobacco industry counteracted this in print with the affable and harmless looking cartoon figure, Joe Camel. That in turn led to the Tobacco Master Settlement Agreement in 1998, prohibiting ads that might appeal to underage smokers, as well as billboard advertising.

For now, the scales have tipped to the advocates for public health. The percentage of American adults who smoke declined from 42% in 1965 to 18% in 2012. But the tobacco industry continues to change both its message and its methods.

E-cigarettes, which deliver a nicotine-rich vapor derived from tobacco plants, have become that latest battleground. Among high school students, e-cigarette use climbed sharply from 4.5% in 2013 to 13.4% just a year later, according to the Centers for Disease Control and Prevention.

Back to promote them are some familiar advertising themes. Stethoscope-wearing physicians promote e-cigarettes as healthier than tobacco products. Famous actors give grinning endorsements. And the product pitches itself to the next generation with bubble gum and apple flavors, much as traditional manufacturers once drew younger smokers with clove- and vanilla-flavored cigarettes.

Now the FDA is moving to regulate electronic cigarettes. One of the first steps will be for e-cigarettes to sport what first appeared on packs of cigarettes five decades ago: health warnings.