As you may recall from earlier this year after Walmart changed their firearm sales policy to include a minimum age of 21, a 20-year-old man from Oregon sued the retailer for age discrimination. He wasn’t the only one, with similar suits cropping up in Illinois and elsewhere. These are complicated cases that are still playing out, but the playing field may be getting a bit wider. Washington State has now decided to imitate Walmart and raise the statewide minimum age for gun purchases to 21.

Washington on Tuesday joined a handful of other states that ban anyone under 21 from buying a semi-automatic assault rifle after voters passed a sweeping firearms measure in November that has drawn a court challenge from gun-rights advocates.

The ballot initiative seeks to curb gun violence by toughening background checks for people buying assault rifles, increasing the age limit to buy those firearms and requiring the safe storage of all guns. Only the age-limit portion of the measure goes into effect on Jan. 1; the rest becomes law on July 1.

Kristen Ellingboe, a spokeswoman for the Washington Alliance for Gun Responsibility, said the initiative was one of the most comprehensive gun-violence prevention measures to pass in the United States. It specifically targeted “semi-automatic assault rifles” in response to mass shootings across the country, she said.

At first glance, you’d think that Washington’s law would be in the clear because the case from Oregon was based on public accommodation laws rather than any Second Amendment considerations. As I discussed in the linked article from May, Oregon has a law prohibiting companies from discriminating on the basis of age. Washington State is not on the list of states with such laws in place. (See this article from Doug Mataconis for more on that subject.)

But today’s story is different. This isn’t a company refusing to provide service. It’s the state government attempting to limit the ability of legal adults. So does that make it a Second Amendment issue dooming Washington to failure? I’m afraid not. Federal law sets the minimum age to purchase a handgun at 21 and 18 for a long rifle. But that’s only a floor, not a ceiling. The states can raise the minimum age to 21 if they wish.

So at the end of the day, there may well be a lawsuit brought against Washington State for this change, but I wouldn’t give it much of a chance at succeeding. Hawaii and Illinois have already had such laws for a while now and Florida recently jumped into that battle. The Supreme Court has thus far refused to hear a case on this specific subject, but there’s a lot of established law backing up the states on this.