No federal law prohibits age discrimination with respect to raising the age for gun sale purchases from 18 to 21.
The federal law that protects Americans from age discrimination is the Age Discrimination in Employment Act of 1967, which applies only to workers who are aged 40 and over. It does not protect Americans under the age of 40 from age discrimination.
What about lawsuits filed against gun sellers in states like Oregon, where a state law prohibits discrimination against individuals aged 18 and older?
A half-dozen states, including Oregon, have passed laws raising the age for cigarette purchases from 18 to 21. Cigarettes kill almost a half million people a year, including more than 41,000 nonsmokers who die from secondhand smoke. The ever litigious tobacco industry has not challenged Tobacco 21 laws on discrimination grounds.
Like Tobacco 21 laws, state laws placing reasonable age restrictions on gun purchases reflect an important public health interest. So far this year, there have been 18 school shootings, the latest being a mass shooting at a Florida high school that killed 17 people. The U.S. Centers for Disease Control and Prevention estimates that an average of 35,141 Americans are killed by guns each year.
It is extremely unlikely the U.S. Supreme Court would overrule a state law that creates an age-based prohibition on gun sales on equal protection grounds. The Court accords age its lowest standard of review so a state law that discriminates based on age need only be rational. It is at least rational to raise the age of gun sales to 21 in an effort to prevent more school shootings. It is arguably irrational NOT TO do so.
Lawsuits alleging age discrimination with respect to raising the age for gun sale purchases would seem to have little chance of success and might even be considered frivolous.