The Supreme Court disappointed gun rights activists once again Monday, declining to review two cases involving the rights of those under 21 to own handguns.

Activists had urged the court to accept the cases, saying there has been a “massive judicial resistance” to expanding gun rights following the Supreme Court’s decision in 2008 that there is a right to gun ownership for self-defense at least within one’s home. In 2010, the court said the right applies to state and local gun-control efforts, not just those at the federal level.

But since then, the court has declined to review unsuccessful efforts to challenge restrictions, such as tight controls on who may carry a firearm in public.

At issue Monday were two such challenges. One involved a Texas law that bars almost all 18-, 19- and 20-year-olds from getting a permit to carry a handgun. The U.S. Court of Appeals for the 5th Circuit upheld the state law, which exempts people with military experience.

The other involved a federal law that prohibits licensed firearms dealers from selling handguns to people under 21. The dealers may sell rifles and shotguns to those 18 and over. The 1968 law banning handgun sales to adults under 21 was prompted by Congress’s finding that such laws were a logical effort to diminish violent crime.

After millions of dollars and more than 10 years of research, there are finally smart guns for the public. But there are only two viable systems available for the public to purchase. (Jason Aldag/The Washington Post)

It, too, was upheld by the appeals court, but over strenuous objections by conservative judges. Both petitions asking the Supreme Court to intervene were filed by the National Rifle Association.

The petitions expressed frustration that gun-control laws were still mostly intact years after the Supreme Court’s ruling in District of Columbia v. Heller, which struck down the District’s ban on handguns.

“Given the number of laws enacted by the federal government, states, and localities in the years when a mistaken understanding of the Second Amendment held sway, one would have expected a major reconsideration of extant firearms laws to have occurred,” Washington lawyer Paul D. Clement wrote in the challenge of the federal law.

“Instead, jurisdictions have engaged in massive resistance to the clear import of those landmark decisions, and the lower federal courts, long out of the habit of taking the Second Amendment seriously, have largely facilitated the resistance.”

The cases are NRA v. Bureau of Alcohol, Tobacco, Firearms and Explosives and NRA v. McGraw.

The court also declined to review Lane v. Holder, in which D.C. residents challenged federal laws that restrict buying a firearm from an out-of-state dealer.

Class-action lawsuits

Also on Monday, the justices refused an industry request that they step in to stop class-action lawsuits from consumers who complain about a musty smell from front-loading washing machines.

Business groups told the court that the suits were so large that they could involve consumers who had never had a problem with the washers. The groups asked the court to accept the cases and rein in the big suits.

But the justices without comment refused the petitions from Sears, Whirlpool and German manufacturer Bosch and Siemens. That means the suits, which had been upheld by the federal appeals courts for the 6th and 7th circuits, may proceed.

The suits cover machines manufactured between 2001 and 2008. One suit involved Ohio consumers; the other covers those who purchased machines in California, Minnesota, Illinois, Indiana, Kentucky and Texas. The Bosch suit covers consumers in California, Illinois, New York and Maryland.

The consumers charge that a design defect makes the machines likely to develop mold. It was only after they bought the washers, they say, that they learned special care was required to keep the appliances from developing mold and a musty smell.

“In those post-sale instructions, Whirlpool directed all purchasers that they must: clean the exterior, interior, door seal, and dispenser drawer; wipe the machine down after each use; leave the door open between uses; run monthly maintenance cycles; and run cycles with Affresh cleaning tablets,” the consumer brief told the court.

Whirlpool contended that it provided customers with information for any easy fix — most front-loader owners know now to leave the door open after use — and that the class of plaintiffs was far too broad.

Liability “depends on individualized issues that permeate plaintiffs’ claims and Whirlpool’s defenses,” the company said in its petition.

The U.S. Chamber of Commerce was among the business organizations that had told the court it was important to review lower-court decisions allowing the suits to advance.

“If allowed to stand, the decisions will dramatically increase the class-action exposure faced by [Chamber] members who sell or manufacture products in interstate commerce, including in cases where there is no proof that any meaningful number of putative class members have suffered harm,” the organization said.