WASHINGTON — A federal appeals court ruled Tuesday that the long-standing federal ban on sales of handguns from licensed dealers to 18- to 20-year-olds is unconstitutional, because Congress in the 1960s did not demonstrate a good enough reason for the law.

In a 2-1 ruling, a three-judge panel of the U.S. Court of Appeals for the 4th Circuit, based in Richmond, Virginia, found that the Second Amendment’s right to keep and bear arms is no different from other constitutional rights that start at age 18, so the government must have a justification to restrict that right.

“Despite the weighty interest in reducing crime and violence, we refuse to relegate either the Second Amendment or 18- to 20-year-olds to a second-class status,” Judge Julius Richardson wrote for the majority.

Richardson, a President Donald Trump appointee, was joined in the majority opinion by Judge G. Stephen Agee, a President George W. Bush appointee.

Judge James Wynn Jr., a President Barack Obama appointee, wrote a dissent that said the panel had overstepped its role as a court, and that “the majority’s decision to grant the gun lobby a victory in a fight it lost on Capitol Hill more than 50 years ago is not compelled by law.”

The Justice Department will almost certainly appeal the decision, which comes during an incendiary national debate over gun control laws prompted by everyday shootings as well as a series of mass shootings over the years at concerts, schools and other public spaces.

The Supreme Court, with a newly expanded 6-3 conservative majority, has teed up a major case about state concealed carry laws for the term that starts in October that will be a test of how far the justices might extend constitutional gun rights outside the home.